Problem:
 Score : 100 points    Problem Statement Consider a string of length N consisting of 0 and 1 .
The score for the string is calculated as follows:   For each i ( 1 \leq i \leq M ), a_i is added to the score if the string contains 1 at least once between the l_i -th and r_i -th characters (inclusive).   Find the maximum possible score of a string.      Constraints  All values in input are integers.  1 \leq N \leq 2 × 10^5  1 \leq M \leq 2 × 10^5  1 \leq l_i \leq r_i \leq N  |a_i| \leq 10^9         Input Input is given from Standard Input in the following format:  N  M  l_1  r_1  a_1  l_2  r_2  a_2  :  l_M  r_M  a_M       Output Print the maximum possible score of a string.        Sample Input 1 5 3
1 3 10
2 4 -10
3 5 10      Sample Output 1 20  The score for 10001 is a_1 + a_3 = 10 + 10 = 20 .       Sample Input 2 3 4
1 3 100
1 1 -10
2 2 -20
3 3 -30      Sample Output 2 90  The score for 100 is a_1 + a_2 = 100 + (-10) = 90 .       Sample Input 3 1 1
1 1 -10      Sample Output 3 0  The score for 0 is 0 .       Sample Input 4 1 5
1 1 1000000000
1 1 1000000000
1 1 1000000000
1 1 1000000000
1 1 1000000000      Sample Output 4 5000000000  The answer may not fit into a 32-bit integer type.       Sample Input 5 6 8
5 5 3
1 1 10
1 6 -8
3 6 5
3 4 9
5 5 -2
1 3 -6
4 6 -7      Sample Output 5 10  For example, the score for 101000 is a_2 + a_3 + a_4 + a_5 + a_7 = 10 + (-8) + 5 + 9 + (-6) = 10 .

Solution (Python):
"""
遅延セグメント木（区間演算、区間更新）
dat[] の要素に モノイド M をもつ
laz[] の要素に Aut(M) をもつ（ただし作用素は「右」から作用とする）
アクセスは0-indexed, 内部のツリーは 1-indexed（つまりすべての和は tree[1]）
関数は閉区間
引数：
    N: 処理する区間の長さ
    op_M = operator: モノイド演算 (max, min, __add__,ラムダ式,関数定義など)
    e_M: 単位元
    compose: 作用素を合成させる関数 (max, min, __add__,ラムダ式,関数定義など)
    funcval(x,f) = f(x) 関数適用
    ID_M: 恒等作用素
"""
""" 作用素の例：
f \mapsto min(f,-)
    compose = min
    funcval = min
    ID_M = INF = 10**18
f \mapsto max(f,-)
    compose = max
    funcval = max
    ID_M = 0
f \mapsto f (定数関数)（区間代入、最後の操作のみが影響する）
compose = lambda f,g: (f if g == ID_M else g)
funcval = lambda x,f: (x if f == ID_M else f)
ID_M = None 
"""

class lazy_segment_tree:
    def __init__(self, N, operator_M, e_M, compose, funcval, ID_M=None):
        self.compose = compose 
        self.ID_M = ID_M       
        self.funcval = funcval 

        self.op_M = operator_M 
        self.e_M = e_M         
        
        self.height = (N-1).bit_length() 
        self.N0 = N0 = 1<<self.height 

        self.dat = [self.e_M]*(2*N0) 
        self.laz = [self.ID_M]*(2*N0) 
        
        """
        length = [N0>>1]*N0
        for i in range(2,N0): length[i] = length[i>>1]>>1
        self.length = length 
        """
        
    
    def build(self, initial):
        self.dat[self.N0:self.N0+len(initial)] = initial[:]
        for k in range(self.N0-1,0,-1):
            self.dat[k] = self.op_M(self.dat[2*k], self.dat[2*k+1])
    
    
    def propagate(self,k):
        if self.laz[k] == self.ID_M: return;
        self.dat[k] = self.reflect(k)
        if self.N0 <= k:
            self.laz[k] = self.ID_M
            return
        else:
            self.laz[2*k  ] = self.compose(self.laz[2*k  ],self.laz[k])
            self.laz[2*k+1] = self.compose(self.laz[2*k+1],self.laz[k])
            self.laz[k] = self.ID_M
            return
        
    
    def propagate_all(self):
        for i in range(1,2*self.N0): self.propagate(i)
    
    
    def thrust(self,k):
        for i in range(self.height,-1,-1): self.propagate(k>>i)

    def thrust2(self,L,R):
        for i in range(self.height,0,-1):
            self.propagate(L>>i)
            if (L>>i) != R>>i:
                self.propagate(R>>i)

    
    def update(self, l,r,f):
        l += self.N0; r += self.N0
        
        
        
        
        L = l; R = r+1
        
        while L < R:
            if R & 1:
                R -= 1
                self.laz[R] = self.compose(self.laz[R], f)
            if L & 1:
                self.laz[L] = self.compose(self.laz[L], f)
                L += 1
            L >>= 1; R >>= 1
        
        
        self.recalc_dat2(l,r)
        
    def reflect(self,k):
        if self.laz[k] == self.ID_M: return self.dat[k]
        else: return self.funcval(self.dat[k],self.laz[k])
        
    
    def recalc_dat(self,k):
        k //= 2
        while k:
            self.dat[k] = self.op_M(self.funcval(self.dat[2*k],self.laz[2*k]),self.funcval(self.dat[2*k+1],self.laz[2*k+1]))
            
            k //= 2

    def recalc_dat2(self,l,r):
        l //= 2; r //= 2
        while l:
            
            self.dat[l] = self.op_M(self.funcval(self.dat[2*l],self.laz[2*l]),self.funcval(self.dat[2*l+1],self.laz[2*l+1]))
            if l != r:
                
                self.dat[r] = self.op_M(self.funcval(self.dat[2*r],self.laz[2*r]),self.funcval(self.dat[2*r+1],self.laz[2*r+1]))
            l //= 2; r //= 2

    
    def point_get(self, k):
        k += self.N0
        res = self.dat[k]
        while k:
            if self.laz[k] != self.ID_M:
                res = self.funcval(res, self.laz[k])
            k //= 2
        return res
    
    
    def point_set(self, k,x): 
        k += self.N0
        self.thrust(k)
        self.dat[k] = x
        self.recalc_dat(k)

    
    def query(self, L,R):
        L += self.N0; R += self.N0 + 1 
        self.thrust2(L,R)
        
        sl = sr = self.e_M
        while L < R:
            if R & 1:
                R -= 1
                sr = self.op_M(self.reflect(R),sr)
            if L & 1:
                sl = self.op_M(sl,self.reflect(L))
                L += 1
            L >>= 1; R >>= 1
        return self.op_M(sl,sr)




import sys
sys.setrecursionlimit(10**6)
readline = sys.stdin.buffer.readline 

n,m = [int(i) for i in readline().split()]
lra = [tuple(int(i) for i in readline().split()) for _ in range(m)]

from operator import add, itemgetter
operator_M = max
compose = add
funcval = add
ID_M = 0
e_M = -10**18

seg = lazy_segment_tree(n+1, operator_M, e_M, compose, funcval, ID_M)
seg.build([0]+[ID_M]*(n))



ans = [] 

lra.sort(key = itemgetter(1))

j = 0

"""
N0 = self.N0
self.thrust(k)
self.dat[k] = x
self.recalc_dat(k)
"""

N0 = seg.N0
for i in range(1,n+1):
    
    
    
    seg.dat[i+N0] = seg.query(0,i-1)
    seg.recalc_dat(i+N0)
    
    while j < m and i == lra[j][1]:
        
        seg.update(*lra[j])
        j += 1

seg.propagate_all()
print(max(seg.dat[seg.N0:seg.N0+n+1]))

Solution (Python):
"""
遅延セグメント木（区間演算、区間更新）
dat[] の要素に モノイド M をもつ
laz[] の要素に Aut(M) をもつ（ただし作用素は「右」から作用とする）
アクセスは0-indexed, 内部のツリーは 1-indexed（つまりすべての和は tree[1]）
関数は閉区間
引数：
    N: 処理する区間の長さ
    op_M = operator: モノイド演算 (max, min, __add__,ラムダ式,関数定義など)
    e_M: 単位元
    compose: 作用素を合成させる関数 (max, min, __add__,ラムダ式,関数定義など)
    funcval(x,f) = f(x) 関数適用
    ID_M: 恒等作用素
"""
""" 作用素の例：
f \mapsto min(f,-)
    compose = min
    funcval = min
    ID_M = INF = 10**18
f \mapsto max(f,-)
    compose = max
    funcval = max
    ID_M = 0
f \mapsto f (定数関数)（区間代入、最後の操作のみが影響する）
compose = lambda f,g: (f if g == ID_M else g)
funcval = lambda x,f: (x if f == ID_M else f)
ID_M = None 
"""

class lazy_segment_tree:
    def __init__(self, N, operator_M, e_M, compose, funcval, ID_M=None):
        self.compose = compose 
        self.ID_M = ID_M       
        self.funcval = funcval 

        self.op_M = operator_M 
        self.e_M = e_M         
        
        self.height = (N-1).bit_length() 
        self.N0 = N0 = 1<<self.height 

        self.dat = [self.e_M]*(2*N0) 
        self.laz = [self.ID_M]*(2*N0) 
        
        """
        length = [N0>>1]*N0
        for i in range(2,N0): length[i] = length[i>>1]>>1
        self.length = length 
        """
        
    
    def build(self, initial):
        self.dat[self.N0:self.N0+len(initial)] = initial[:]
        for k in range(self.N0-1,0,-1):
            self.dat[k] = self.op_M(self.dat[2*k], self.dat[2*k+1])
    
    
    def propagate(self,k):
        if self.laz[k] == self.ID_M: return;
        self.dat[k] = self.reflect(k)
        if self.N0 <= k:
            self.laz[k] = self.ID_M
            return
        else:
            self.laz[2*k  ] = self.compose(self.laz[2*k  ],self.laz[k])
            self.laz[2*k+1] = self.compose(self.laz[2*k+1],self.laz[k])
            self.laz[k] = self.ID_M
            return
        
    
    def propagate_all(self):
        for i in range(1,2*self.N0): self.propagate(i)
    
    
    def thrust(self,k):
        for i in range(self.height,-1,-1): self.propagate(k>>i)

    def thrust2(self,L,R):
        for i in range(self.height,0,-1):
            self.propagate(L>>i)
            if (L>>i) != R>>i:
                self.propagate(R>>i)

    
    def update(self, l,r,f):
        l += self.N0; r += self.N0
        
        
        self.thrust2(l,r)
        L = l; R = r+1
        
        while L < R:
            if R & 1:
                R -= 1
                self.laz[R] = self.compose(self.laz[R], f)
            if L & 1:
                self.laz[L] = self.compose(self.laz[L], f)
                L += 1
            L >>= 1; R >>= 1
        
        
        self.recalc_dat2(l,r)
        
    def reflect(self,k):
        if self.laz[k] == self.ID_M: return self.dat[k]
        else: return self.funcval(self.dat[k],self.laz[k])
        
    
    def recalc_dat(self,k):
        k //= 2
        while k:
            self.dat[k] = self.op_M(self.funcval(self.dat[2*k],self.laz[2*k]),self.funcval(self.dat[2*k+1],self.laz[2*k+1]))
            
            k //= 2

    def recalc_dat2(self,l,r):
        l //= 2; r //= 2
        while l:
            
            self.dat[l] = self.op_M(self.funcval(self.dat[2*l],self.laz[2*l]),self.funcval(self.dat[2*l+1],self.laz[2*l+1]))
            if l != r:
                
                self.dat[r] = self.op_M(self.funcval(self.dat[2*r],self.laz[2*r]),self.funcval(self.dat[2*r+1],self.laz[2*r+1]))
            l //= 2; r //= 2

    
    def point_get(self, k):
        k += self.N0
        res = self.dat[k]
        while k:
            if self.laz[k] != self.ID_M:
                res = self.funcval(res, self.laz[k])
            k //= 2
        return res
    
    
    def point_set(self, k,x): 
        k += self.N0
        self.thrust(k)
        self.dat[k] = x
        self.recalc_dat(k)

    
    def query(self, L,R):
        L += self.N0; R += self.N0 + 1 
        self.thrust2(L,R)
        
        sl = sr = self.e_M
        while L < R:
            if R & 1:
                R -= 1
                sr = self.op_M(self.reflect(R),sr)
            if L & 1:
                sl = self.op_M(sl,self.reflect(L))
                L += 1
            L >>= 1; R >>= 1
        return self.op_M(sl,sr)




import sys
sys.setrecursionlimit(10**6)
readline = sys.stdin.buffer.readline 

n,m = [int(i) for i in readline().split()]
lra = [tuple(int(i) for i in readline().split()) for _ in range(m)]

from operator import add, itemgetter
operator_M = max
compose = add
funcval = add
ID_M = 0
e_M = -10**18

seg = lazy_segment_tree(n+1, operator_M, e_M, compose, funcval, ID_M)
seg.build([0]+[ID_M]*(n))



ans = [] 

lra.sort(key = itemgetter(1))

j = 0

"""
N0 = self.N0
self.thrust(k)
self.dat[k] = x
self.recalc_dat(k)
"""

N0 = seg.N0
for i in range(1,n+1):
    
    
    
    seg.dat[i+N0] = seg.query(0,i-1)
    seg.recalc_dat(i+N0)
    
    while j < m and i == lra[j][1]:
        
        seg.update(*lra[j])
        j += 1

seg.propagate_all()
print(max(seg.dat[seg.N0:seg.N0+n+1]))

Solution (Python):

import sys
 
class LazySegmentTree:
    def __init__(self,n):
        n2=1<<n.bit_length()
        self.n=n2
        self.offset=n2
        self.data=[0]*(n2<<1)
        self.lazy=[0]*(n2<<1)
 
        update_base=[0]*n
        propagate_indices=[[] for _ in [0]*n]
        update_indices=[[] for _ in [0]*n]
        for i in range(n):
            j=i+n2+1
            b=(j>>(-j&j).bit_length()-1)-1
            update_base[i]=b
            while b>1:
                b>>=1
                propagate_indices[i].append(b)
        for i in range(n):
            k=i+1
            while k:
                update_indices[i].append(update_base[k-1])
                k-=-k&k
        self.propagate_indices=propagate_indices
        self.update_indices=update_indices
 
    def _push(self,k):
        for i in reversed(self.propagate_indices[k]):
            v=self.lazy[i]
            if v==0:
                continue
            j=i<<1
            self.data[j]+=v
            self.data[j+1]+=v
            self.lazy[j]+=v
            self.lazy[j+1]+=v
            self.lazy[i]=0
 
    def add(self,k,x):
        for i in self.update_indices[k]:
            self.data[i]+=x
            self.lazy[i]+=x
        for i in self.propagate_indices[k]:
            self.data[i]=max(self.data[i*2],self.data[i*2+1])+self.lazy[i]
 
    def get(self,k):
        self._push(k)
        ret=max(map(self.data.__getitem__, self.update_indices[k]))
        i=k+self.offset+1
        self.data[i]+=ret
        tmp=self.data[i]
        while i>1:
            parent=i>>1
            sibling=i^1
            tmp=self.data[parent]=max(tmp, self.data[sibling])+self.lazy[parent]
            i=parent
        return ret
 
 
 
 
n,m=map(int,input().split())
range_ls=[0 for _ in [0]*n]
range_rs=[[] for _ in [0]*n]
 
for line in sys.stdin.readlines():
    l,r,a=map(int, line.split())
    range_ls[l-1]+=a
    range_rs[r-1].append((l-1,a))
 
lst=LazySegmentTree(n)
ans=0
 
for i, (la,rs) in enumerate(zip(range_ls,range_rs)):
    if la!=0:
        lst.add(i,la)
    ans=max(ans,lst.get(i))
    for l,a in rs:
        lst.add(l,-a)
print(ans)

Solution (Python):
import sys
input = sys.stdin.readline
sys.setrecursionlimit(10 ** 7)

N,M = map(int,input().split())
LRA = [[int(x) for x in row.split()] for row in sys.stdin.readlines()]

R_to_LA = [[] for _ in range(N+1)]
for L,R,A in LRA:
    R_to_LA[R].append((L,A))

INF = 10 ** 18

size = 1<<18
data = [0] * (2*size)
lazy = [0] * (2*size)
left_end = [None] * (2*size)
right_end = [None] * (2*size)
left_end[1] = 0
right_end[1] = size
for n in range(1,size):
    L,R = left_end[n],right_end[n]
    M = (L+R)//2
    left_end[2*n] = L
    right_end[2*n] = M
    left_end[2*n+1] = M
    right_end[2*n+1] = R

def add(L,R,x):
    q = [1]
    q1 = []
    while q:
        qq = []
        for i in q:
            iL = left_end[i]
            iR = right_end[i]
            if L <= iL and iR <= R:
                
                lazy[i] += x
            elif iR<=L or R<=iL:
                pass
            else:
                
                q1.append(i)
                j = i<<1; k = j+1
                lazy[j] += lazy[i]; lazy[k] += lazy[i]
                lazy[i] = 0
                qq.append(j)
                qq.append(k)
        q = qq
    for i in reversed(q1):
        j = i<<1; k = j+1
        data[i] = max(data[j]+lazy[j],data[k]+lazy[k])

for R in range(1,N+1):
    x = data[1] + lazy[1]
    add(R,R+1,x)
    for L,A in R_to_LA[R]:
        add(L,R+1,A)

for n in range(size):
    lazy[2*n] += lazy[n]
    lazy[2*n+1] += lazy[n]

answer = max(lazy[size:])
print(answer)

Solution (Python):
import sys
class Lazysegtree:
    
    def __init__(self, A, intv, initialize = True, segf = min):
        
        self.N = len(A)
        self.N0 = 2**(self.N-1).bit_length()
        self.intv = intv
        self.segf = segf
        self.lazy = [0]*(2*self.N0)
        if initialize:
            self.data = [intv]*self.N0 + A + [intv]*(self.N0 - self.N)
            for i in range(self.N0-1, 0, -1):
                self.data[i] = self.segf(self.data[2*i], self.data[2*i+1]) 
        else:
            self.data = [intv]*(2*self.N0)

    def _ascend(self, k):
        k = k >> 1
        c = k.bit_length()
        for j in range(c):
            idx = k >> j
            self.data[idx] = self.segf(self.data[2*idx], self.data[2*idx+1]) \
            + self.lazy[idx]
            
    def _descend(self, k):
        k = k >> 1
        idx = 1
        c = k.bit_length()
        for j in range(1, c+1):
            idx = k >> (c - j)
            ax = self.lazy[idx]
            if not ax:
                continue
            self.lazy[idx] = 0
            self.data[2*idx] += ax
            self.data[2*idx+1] += ax
            self.lazy[2*idx] += ax
            self.lazy[2*idx+1] += ax
    
    def update(self, k, x):
        k = k + self.N0
        self.data[k] = x
        self._ascend(k)
    
    def query(self, l, r):
        L = l+self.N0
        R = r+self.N0
        Li = L//(L & -L)
        Ri = R//(R & -R)
        self._descend(Li)
        self._descend(Ri - 1)
        
        s = self.intv                                                              
        while L < R:
            if R & 1:
                R -= 1
                s = self.segf(s, self.data[R])
            if L & 1:
                s = self.segf(s, self.data[L])
                L += 1
            L >>= 1
            R >>= 1
        return s
    
    def add(self, l, r, x):
        L = l+self.N0
        R = r+self.N0

        Li = L//(L & -L)
        Ri = R//(R & -R)
        
        while L < R :
            if R & 1:
                R -= 1
                self.data[R] += x
                self.lazy[R] += x
            if L & 1:
                self.data[L] += x
                self.lazy[L] += x
                L += 1
            L >>= 1
            R >>= 1
        
        self._ascend(Li)
        self._ascend(Ri-1)

N, M = map(int, input().split())
LA = [[] for _ in range(N)]
for _ in range(M):
    l, r, a = map(int, sys.stdin.readline().split())
    LA[r-1].append((l-1, a))

dp = Lazysegtree([0]*(N+1), -10**16, True, max)

for i in range(N):
    res = 0
    t = dp.data[1]
    for l, a in LA[i]:
        res += a
        dp.add(l, i, a)
    dp.update(i, res + t)
print(dp.data[1])

Solution (Python):
import sys
class Lazysegtree:
    
    def __init__(self, A, intv, initialize = True, segf = min):
        
        self.N = len(A)
        self.N0 = 2**(self.N-1).bit_length()
        self.intv = intv
        self.segf = segf
        self.lazy = [0]*(2*self.N0)
        if initialize:
            self.data = [intv]*self.N0 + A + [intv]*(self.N0 - self.N)
            for i in range(self.N0-1, 0, -1):
                self.data[i] = self.segf(self.data[2*i], self.data[2*i+1]) 
        else:
            self.data = [intv]*(2*self.N0)

    def _ascend(self, k):
        k = k >> 1
        c = k.bit_length()
        for j in range(c):
            idx = k >> j
            self.data[idx] = self.segf(self.data[2*idx], self.data[2*idx+1]) \
            + self.lazy[idx]
            
    def _descend(self, k):
        k = k >> 1
        idx = 1
        c = k.bit_length()
        for j in range(1, c+1):
            idx = k >> (c - j)
            ax = self.lazy[idx]
            if not ax:
                continue
            self.lazy[idx] = 0
            self.data[2*idx] += ax
            self.data[2*idx+1] += ax
            self.lazy[2*idx] += ax
            self.lazy[2*idx+1] += ax
    
    def update(self, k, x):
        k = k + self.N0
        self.data[k] = x
        self._ascend(k)
    
    def query(self, l, r):
        L = l+self.N0
        R = r+self.N0
        Li = L//(L & -L)
        Ri = R//(R & -R)
        self._descend(Li)
        self._descend(Ri - 1)
        
        s = self.intv                                                              
        while L < R:
            if R & 1:
                R -= 1
                s = self.segf(s, self.data[R])
            if L & 1:
                s = self.segf(s, self.data[L])
                L += 1
            L >>= 1
            R >>= 1
        return s
    
    def add(self, l, r, x):
        L = l+self.N0
        R = r+self.N0

        Li = L//(L & -L)
        Ri = R//(R & -R)
        
        while L < R :
            if R & 1:
                R -= 1
                self.data[R] += x
                self.lazy[R] += x
            if L & 1:
                self.data[L] += x
                self.lazy[L] += x
                L += 1
            L >>= 1
            R >>= 1
        
        self._ascend(Li)
        self._ascend(Ri-1)
N, M = map(int, input().split())
LA = [[] for _ in range(N)]
for _ in range(M):
    l, r, a = map(int, sys.stdin.readline().split())
    LA[r-1].append((l-1, a))

dp = Lazysegtree([0]*(N+1), -10**16, True, max)

for i in range(N):
    res = 0
    t = dp.data[1]
    for l, a in LA[i]:
        res += a
        dp.add(l, i, a)
    dp.add(i,i+1, res + t)
print(dp.data[1])

Solution (Python):
class StarrySkyTree:
    def __init__(self,num):
        leaf=1<<(num-1).bit_length()
        self.leaf=leaf
        self.data=[0]*leaf*2
        self.lazy=[0]*leaf*2
    def indices(self,l,r):
        L,R=l+self.leaf,r+self.leaf
        lm=(L//(L&-L))>>1
        rm=(R//(R&-R))>>1
        while L<R:
            if R<=rm:
                yield R
            if L<=lm:
                yield L
            L>>=1; R>>=1
        while L:
            yield L
            L>>=1
    def zeroindices(self,k):
        K=k+self.leaf
        limit=(K//(K&-K))>>1
        while K:
            if K<=limit:
                yield K
            K>>=1
    def _propagates(self,*ids):
        for i in reversed(ids):
            v=self.lazy[i-1]
            if v==0:
                continue
            self.lazy[2*i-1]+=v; self.lazy[2*i]+=v
            self.data[2*i-1]+=v; self.data[2*i]+=v
            self.lazy[i-1]=0
    def add(self,l,r,x):
        L,R=l+self.leaf,r+self.leaf
        while L<R:
            if L&1:
                self.lazy[L-1]+=x; self.data[L-1]+=x
                L+=1
            if R&1:
                R-=1
                self.lazy[R-1]+=x; self.data[R-1]+=x
            L>>=1; R>>=1
        for i in self.indices(l,r):
            self.data[i-1]=max(self.data[2*i-1],self.data[2*i])+self.lazy[i-1]
    def add1(self,k,x):
        k+=self.leaf
        self.data[k-1]+=x
        while k:
            k>>=1
            self.data[k-1]=max(self.data[2*k-1],self.data[2*k])+self.lazy[k-1]
    def query0(self,k):
        self._propagates(*self.zeroindices(k))
        L,R=self.leaf,k+self.leaf
        ret=0
        while L<R:
            if L&1:
                ret=max(ret,self.data[L-1])
                L+=1
            if R&1:
                R-=1
                ret=max(ret,self.data[R-1])
            L>>=1; R>>=1
        return ret

import sys
input=sys.stdin.readline
n,m=map(int,input().split())
sst=StarrySkyTree(n+1)
R=[[] for _ in range(n+1)]
for _ in range(m):
    l,r,a=map(int,input().split())
    R[r].append((l,a))
for i in range(1,n+1):
    v=sst.query0(i)
    sst.add1(i,v)
    for l,a in R[i]:
        sst.add(l,i+1,a)
print(sst.query0(n+1))

Solution (Python):
class StarrySkyTree:
    def __init__(self,num):
        leaf=1<<(num-1).bit_length()
        self.leaf=leaf
        self.data=[0]*leaf*2
        self.lazy=[0]*leaf*2
    def indices(self,l,r):
        L,R=l+self.leaf,r+self.leaf
        lm=(L//(L&-L))>>1
        rm=(R//(R&-R))>>1
        while L<R:
            if R<=rm:
                yield R
            if L<=lm:
                yield L
            L>>=1; R>>=1
        while L:
            yield L
            L>>=1
    def zeroindices(self,k):
        K=k+self.leaf
        limit=(K//(K&-K))>>1
        while K:
            if K<=limit:
                yield K
            K>>=1
    def _propagates(self,*ids):
        for i in reversed(ids):
            v=self.lazy[i-1]
            if v==0:
                continue
            self.lazy[2*i-1]+=v; self.lazy[2*i]+=v
            self.data[2*i-1]+=v; self.data[2*i]+=v
            self.lazy[i-1]=0
    def add(self,l,r,x):
        L,R=l+self.leaf,r+self.leaf
        while L<R:
            if L&1:
                self.lazy[L-1]+=x; self.data[L-1]+=x
                L+=1
            if R&1:
                R-=1
                self.lazy[R-1]+=x; self.data[R-1]+=x
            L>>=1; R>>=1
        for i in self.indices(l,r):
            self.data[i-1]=max(self.data[2*i-1],self.data[2*i])+self.lazy[i-1]
    def add1(self,k,x): 
        k+=self.leaf
        self.data[k-1]+=x
        while k:
            k>>=1
            self.data[k-1]=max(self.data[2*k-1],self.data[2*k])+self.lazy[k-1]
    def query(self,l,r): 
        self._propagates(*self.indices(l,r))
        L,R=l+self.leaf,r+self.leaf
        ret=0
        while L<R:
            if L&1:
                ret=max(ret,self.data[L-1])
                L+=1
            if R&1:
                R-=1
                ret=max(ret,self.data[R-1])
            L>>=1; R>>=1
        return ret
    def query0(self,k):
        self._propagates(*self.zeroindices(k))
        L,R=self.leaf,k+self.leaf
        ret=0
        while L<R:
            if L&1:
                ret=max(ret,self.data[L-1])
                L+=1
            if R&1:
                R-=1
                ret=max(ret,self.data[R-1])
            L>>=1; R>>=1
        return ret

import sys
input=sys.stdin.readline
n,m=map(int,input().split())
sst=StarrySkyTree(n+1)
R=[[] for _ in range(n+1)]
for _ in range(m):
    l,r,a=map(int,input().split())
    R[r].append((l,a))
for i in range(1,n+1):
    v=sst.query0(i)
    sst.add1(i,v)
    for l,a in R[i]:
        sst.add(l,i+1,a)
print(sst.query0(n+1))

Solution (Python):
import sys
input = sys.stdin.readline

N,M=map(int,input().split())

end=[[] for i in range(N+2)]

for i in [0]*M:
    l,r,a=map(int,input().split())
    end[r+1].append((l,a))


seg_el=1<<18

SEG=[0]*(2*seg_el-1)
ADD=[0]*(2*seg_el-1)
seg_el_list=[524286, 262142, 131070, 65534, 32766, 16382, 8190, 4094, 2046, 1022, 510, 254, 126, 62, 30, 14, 6, 2, 0]

def update(k):
    while k>=0:
        k=(k-1)//2
        if SEG[k]==max(SEG[k*2+1]+ADD[k*2+1],SEG[k*2+2]+ADD[k*2+2]):
            break
        SEG[k]=max(SEG[k*2+1]+ADD[k*2+1],SEG[k*2+2]+ADD[k*2+2])

def to_seg(a):
    b=(a&(-a)).bit_length()
    return seg_el_list[b]+a//(1<<(b-1))

def add(a,b,x):
    
    while b!=0:
        ADD[to_seg(b)]+=x
        update(to_seg(b))
        b-=(b&(-b))

    while a!=0:
        ADD[to_seg(a)]+=-x
        update(to_seg(a))
        a-=(a&(-a))
    
for i in range(N+2):
    for b,k in end[i]:
        add(b,i,k)

    SEG[i+seg_el-1]=SEG[0]
    update(i+seg_el-1)

print(SEG[0])

Solution (Python):
import sys


class LazySegmentTree:
    """ [0, k) Add, [0, k) Max """

    
    

    def __init__(self, n):
        n2 = 1 << n.bit_length()
        self.n = n2
        self.offset = n2
        self.data = [0] * (n2 << 1)
        self.lazy = [0] * (n2 << 1)

        update_base = [0] * n
        propagate_indices = [[] for _ in [0] * n]
        update_indices = [[] for _ in [0] * n]
        for i in range(n):
            j = i + n2 + 1
            b = (j >> (j & -j).bit_length() - 1) - 1
            update_base[i] = b
            while b > 1:
                b >>= 1
                propagate_indices[i].append(b)
        for i in range(n):
            k = i + 1
            while k:
                update_indices[i].append(update_base[k - 1])
                k -= k & -k
        self.propagate_indices = propagate_indices
        self.update_indices = update_indices
        
        
        

    def _push(self, k):
        
        for i in reversed(self.propagate_indices[k]):
            v = self.lazy[i]
            if v == 0:
                continue
            j = i << 1
            self.data[j] += v
            self.data[j + 1] += v
            self.lazy[j] += v
            self.lazy[j + 1] += v
            self.lazy[i] = 0

    
    def add(self, k, x):
        
        for i in self.update_indices[k]:
            self.data[i] += x
            self.lazy[i] += x

        for i in self.propagate_indices[k]:
            self.data[i] = max(self.data[i * 2], self.data[i * 2 + 1]) + self.lazy[i]

    
    def get(self, k):
        self._push(k)

        

        ret = max(map(self.data.__getitem__, self.update_indices[k]))
        

        
        i = k + self.offset + 1
        self.data[i] += ret

        tmp = self.data[i]
        while i > 1:
            parent = i >> 1
            sibling = i ^ 1
            tmp = self.data[parent] = max(tmp, self.data[sibling]) + self.lazy[parent]
            i = parent

        return ret

    def _debug_print(self, data):
        a = 1
        while a <= self.offset:
            b = a << 1
            print('   ', data[a:b])
            a = b

    def debug_print(self):
        print('   data')
        self._debug_print(self.data)
        print('   lazy')
        self._debug_print(self.lazy)


n, m = map(int, input().split())
range_ls = [0 for _ in [0] * n]
range_rs = [[] for _ in [0] * n]
for line in sys.stdin.readlines():
    l, r, a = map(int, line.split())
    range_ls[l - 1] += a
    range_rs[r - 1].append((l - 1, a))

lst = LazySegmentTree(n)

ans = 0
for i, (la, rs) in enumerate(zip(range_ls, range_rs)):
    if la != 0:
        lst.add(i, la)
    ans = max(ans, lst.get(i))
    
    
    for l, a in rs:
        lst.add(l, -a)
    
    
print(ans)

Solution (Python):
import sys
readline = sys.stdin.readline

N, M = map(int, readline().split())
L = [[] for i in range(N+1)]
R = [[] for i in range(N+1)]
for i in range(M):
    l, r, a = map(int, readline().split())
    L[l-1].append((r, a))

INF = 2**31-1

LV = (N).bit_length()
N0 = 2**LV
data = [0]*(2*N0)
lazy = [0]*(2*N0)

I = []; J = []
for x in range(N0+1):
    y = N0 + x
    z = (y // (y & -y)) >> 1
    J.append(2*z-1 if z else 0)
    r = []
    while z:
        r.append(z)
        z >>= 1
    r.reverse()
    I.append(r)
I.append([])

def propagates(ids):
    for i in ids:
        v = lazy[i-1]
        if not v:
            continue
        lazy[2*i-1] += v; lazy[2*i] += v
        data[2*i-1] += v; data[2*i] += v
        lazy[i-1] = 0


def update(r, x):
    

    i = r
    while i:
        v = J[i]
        lazy[v] += x; data[v] += x
        i -= (i & -i)

    k = (J[r] + 1) >> 1
    while k:
        data[k-1] = max(data[2*k-1], data[2*k]) + lazy[k-1]
        k >>= 1


def update1(k, x):
    
    k += N0
    data[k-1] += x
    while k:
        k >>= 1
        data[k-1] = max(data[2*k-1], data[2*k]) + lazy[k-1]



def query(r):
    return max(map(data.__getitem__, qquery(r)))

def qquery(r):
    propagates(I[r])

    while r:
        yield J[r]
        r -= (r & -r)


def query1(k, x):
    propagates(I[k])
    return data[k + N0 - 1]


for i in range(N):
    for r, a in L[i]:
        update(i+1, a)
        R[r].append((i, a))
    for l, a in R[i]:
        update(l+1, -a)
    v = query(i+1)
    update1(i+1, v)
for l, a in R[N]:
    update(l+1, -a)
sys.stdout.write("%d\n" % query(N+1))