Buggy python submission (verdict: Time Limit Exceeded):
import sys
input = sys.stdin.readline
class LazySegmentTree():
    def __init__(self, n, op, e, mapping, composition, id):
        self.n = n
        self.op = op
        self.e = e
        self.mapping = mapping
        self.composition = composition
        self.id = id
        self.log = (n - 1).bit_length()
        self.size = 1 << self.log
        self.d = [e] * (2 * self.size)
        self.lz = [id] * (self.size)

    def update(self, k):
#        print(self.d)
        self.d[k] = self.op(self.d[2 * k], self.d[2 * k + 1])

    def all_apply(self, k, f):
        self.d[k] = self.mapping(f, self.d[k])
        if k < self.size:
            self.lz[k] = self.composition(f, self.lz[k])

    def push(self, k):
        self.all_apply(2 * k, self.lz[k])
        self.all_apply(2 * k + 1, self.lz[k])
        self.lz[k] = self.id

    def build(self, arr):
        #assert len(arr) == self.n
        for i, a in enumerate(arr):
            self.d[self.size + i] = a
        for i in range(1, self.size)[::-1]:
            self.update(i)

    def set(self, p, x):
        #assert 0 <= p < self.n
        p += self.size
        for i in range(1, self.log + 1)[::-1]:
            self.push(p >> i)
        self.d[p] = x
        for i in range(1, self.log + 1):
            self.update(p >> i)

    def get(self, p):
        #assert 0 <= p < self.n
        p += self.size
        for i in range(1, self.log + 1):
            self.push(p >> i)
        return self.d[p]

    def prod(self, l, r):
        #assert 0 <= l <= r <= self.n
        if l == r: return self.e
        l += self.size
        r += self.size
        for i in range(1, self.log + 1)[::-1]:
            if ((l >> i) << i) != l: self.push(l >> i)
            if ((r >> i) << i) != r: self.push(r >> i)
        sml = smr = self.e
        while l < r:
            if l & 1:
                sml = self.op(sml, self.d[l])
                l += 1
            if r & 1:
                r -= 1
                smr = self.op(self.d[r], smr)
            l >>= 1
            r >>= 1
        return self.op(sml, smr)

    def all_prod(self):
        return self.d[1]

    def apply(self, p, f):
        #assert 0 <= p < self.n
        p += self.size
        for i in range(1, self.log + 1)[::-1]:
            self.push(p >> i)
        self.d[p] = self.mapping(f, self.d[p])
        for i in range(1, self.log + 1):
            self.update(p >> i)

    def range_apply(self, l, r, f):
        #assert 0 <= l <= r <= self.n
        if l == r: return
        l += self.size
        r += self.size
        for i in range(1, self.log + 1)[::-1]:
            if ((l >> i) << i) != l: self.push(l >> i)
            if ((r >> i) << i) != r: self.push((r - 1) >> i)
        l2 = l
        r2 = r
        while l < r:
            if l & 1:
                self.all_apply(l, f)
                l += 1
            if r & 1:
                r -= 1
                self.all_apply(r, f)
            l >>= 1
            r >>= 1
        l = l2
        r = r2
        for i in range(1, self.log + 1):
            if ((l >> i) << i) != l: self.update(l >> i)
            if ((r >> i) << i) != r: self.update((r - 1) >> i)

    def max_right(self, l, g):
        #assert 0 <= l <= self.n
        #assert g(self.e)
        if l == self.n: return self.n
        l += self.size
        for i in range(1, self.log + 1)[::-1]:
            self.push(l >> i)
        sm = self.e
        while True:
            while l % 2 == 0: l >>= 1
            if not g(self.op(sm, self.d[l])):
                while l < self.size:
                    self.push(l)
                    l = 2 * l
                    if g(self.op(sm, self.d[l])):
                        sm = self.op(sm, self.d[l])
                        l += 1
                return l - self.size
            sm = self.op(sm, self.d[l])
            l += 1
            if (l & -l) == l: return self.n

    def min_left(self, r, g):
        #assert 0 <= r <= self.n
        #assert g(self.e)
        if r == 0: return 0
        r += self.size
        for i in range(1, self.log + 1)[::-1]:
            self.push((r - 1) >> i)
        sm = self.e
        while True:
            r -= 1
            while r > 1 and r % 2: r >>= 1
            if not g(self.op(self.d[r], sm)):
                while r < self.size:
                    self.push(r)
                    r = 2 * r + 1
                    if g(self.op(self.d[r], sm)):
                        sm = self.op(self.d[r], sm)
                        r -= 1
                return r + 1 - self.size
            sm = self.op(self.d[r], sm)
            if (r & -r) == r: return 0

mod = 998244353
N,Q = map(int,input().split())
O = [1]*(N+1)
c=kk=1
for i in range(1, N+1):
    O[i] = c%mod
    kk=kk*10%mod
    c=(c+kk)%mod

def op(x, y):
    return ((pow(10, y[1], mod)*x[0] + y[0]) % mod, x[1]+y[1])

def mapping(p, x):
    if p:
        return (O[x[1]] * p % mod, x[1])
    return x

def composition(p, q):
    if p == 0: return q
    return p

res = [(1, 1)]*N
LST = LazySegmentTree(N,op,(0, 0),mapping,composition,0)
LST.build(res)
for _ in range(Q):
    l,r,D = map(int,input().split())
    LST.range_apply(l-1,r,D)
    print(LST.all_prod()[0])



Fixed submission:
import sys
input = sys.stdin.readline
class LazySegmentTree():
    def __init__(self, n, op, e, mapping, composition, id):
        self.n = n
        self.op = op
        self.e = e
        self.mapping = mapping
        self.composition = composition
        self.id = id
        self.log = (n - 1).bit_length()
        self.size = 1 << self.log
        self.d = [e] * (2 * self.size)
        self.lz = [id] * (self.size)

    def update(self, k):
#        print(self.d)
        self.d[k] = self.op(self.d[2 * k], self.d[2 * k + 1])

    def all_apply(self, k, f):
        self.d[k] = self.mapping(f, self.d[k])
        if k < self.size:
            self.lz[k] = self.composition(f, self.lz[k])

    def push(self, k):
        self.all_apply(2 * k, self.lz[k])
        self.all_apply(2 * k + 1, self.lz[k])
        self.lz[k] = self.id

    def build(self, arr):
        #assert len(arr) == self.n
        for i, a in enumerate(arr):
            self.d[self.size + i] = a
        for i in range(1, self.size)[::-1]:
            self.update(i)

    def set(self, p, x):
        #assert 0 <= p < self.n
        p += self.size
        for i in range(1, self.log + 1)[::-1]:
            self.push(p >> i)
        self.d[p] = x
        for i in range(1, self.log + 1):
            self.update(p >> i)

    def get(self, p):
        #assert 0 <= p < self.n
        p += self.size
        for i in range(1, self.log + 1):
            self.push(p >> i)
        return self.d[p]

    def prod(self, l, r):
        #assert 0 <= l <= r <= self.n
        if l == r: return self.e
        l += self.size
        r += self.size
        for i in range(1, self.log + 1)[::-1]:
            if ((l >> i) << i) != l: self.push(l >> i)
            if ((r >> i) << i) != r: self.push(r >> i)
        sml = smr = self.e
        while l < r:
            if l & 1:
                sml = self.op(sml, self.d[l])
                l += 1
            if r & 1:
                r -= 1
                smr = self.op(self.d[r], smr)
            l >>= 1
            r >>= 1
        return self.op(sml, smr)

    def all_prod(self):
        return self.d[1]

    def apply(self, p, f):
        #assert 0 <= p < self.n
        p += self.size
        for i in range(1, self.log + 1)[::-1]:
            self.push(p >> i)
        self.d[p] = self.mapping(f, self.d[p])
        for i in range(1, self.log + 1):
            self.update(p >> i)

    def range_apply(self, l, r, f):
        #assert 0 <= l <= r <= self.n
        if l == r: return
        l += self.size
        r += self.size
        for i in range(1, self.log + 1)[::-1]:
            if ((l >> i) << i) != l: self.push(l >> i)
            if ((r >> i) << i) != r: self.push((r - 1) >> i)
        l2 = l
        r2 = r
        while l < r:
            if l & 1:
                self.all_apply(l, f)
                l += 1
            if r & 1:
                r -= 1
                self.all_apply(r, f)
            l >>= 1
            r >>= 1
        l = l2
        r = r2
        for i in range(1, self.log + 1):
            if ((l >> i) << i) != l: self.update(l >> i)
            if ((r >> i) << i) != r: self.update((r - 1) >> i)

    def max_right(self, l, g):
        #assert 0 <= l <= self.n
        #assert g(self.e)
        if l == self.n: return self.n
        l += self.size
        for i in range(1, self.log + 1)[::-1]:
            self.push(l >> i)
        sm = self.e
        while True:
            while l % 2 == 0: l >>= 1
            if not g(self.op(sm, self.d[l])):
                while l < self.size:
                    self.push(l)
                    l = 2 * l
                    if g(self.op(sm, self.d[l])):
                        sm = self.op(sm, self.d[l])
                        l += 1
                return l - self.size
            sm = self.op(sm, self.d[l])
            l += 1
            if (l & -l) == l: return self.n

    def min_left(self, r, g):
        #assert 0 <= r <= self.n
        #assert g(self.e)
        if r == 0: return 0
        r += self.size
        for i in range(1, self.log + 1)[::-1]:
            self.push((r - 1) >> i)
        sm = self.e
        while True:
            r -= 1
            while r > 1 and r % 2: r >>= 1
            if not g(self.op(self.d[r], sm)):
                while r < self.size:
                    self.push(r)
                    r = 2 * r + 1
                    if g(self.op(self.d[r], sm)):
                        sm = self.op(self.d[r], sm)
                        r -= 1
                return r + 1 - self.size
            sm = self.op(self.d[r], sm)
            if (r & -r) == r: return 0

mod = 998244353
N,Q = map(int,input().split())
O = [1]*(N+1)
P = [1]*(N+1)
c=kk=1
for i in range(1, N+1):
    O[i] = c
    kk=kk*10%mod
    P[i] = kk
    c=(c+kk)%mod

def op(x, y):
    return ((P[y[1]]*x[0] + y[0]) % mod, x[1]+y[1])

def mapping(p, x):
    if p:
        return (O[x[1]] * p % mod, x[1])
    return x

def composition(p, q):
    if p == 0: return q
    return p

res = [(1, 1)]*N
LST = LazySegmentTree(N,op,(0, 0),mapping,composition,0)
LST.build(res)
for _ in range(Q):
    l,r,D = map(int,input().split())
    LST.range_apply(l-1,r,D)
    print(LST.all_prod()[0])

Buggy python submission (verdict: Runtime Error):

N, Q = map(int, input().split())
LV = (N-1).bit_length()
N0 = 2**LV
data = [(1, 0)]*(2*N0)
lazy = [None]*(2*N0)

def gindex(l, r):
    L = (l + N0) >> 1; R = (r + N0) >> 1
    lc = 0 if l & 1 else (L & -L).bit_length()
    rc = 0 if r & 1 else (R & -R).bit_length()
    for i in range(LV):
        if rc <= i:
            yield R
        if L < R and lc <= i:
            yield L
        L >>= 1; R >>= 1

def propagates(*ids):
    for i in reversed(ids):
        v = lazy[i-1]
        if v is None:
            continue
        lazy[2*i-1] = lazy[2*i] = data[2*i-1] = data[2*i] = v >> 1
        lazy[i-1] = None

def update(l, r, x):
    *ids, = gindex(l, r)
    propagates(*ids)

    L = N0 + l; R = N0 + r
    v = x
    while L < R:
        if R & 1:
            R -= 1
            lazy[R-1] = data[R-1] = v
        if L & 1:
            lazy[L-1] = data[L-1] = v
            L += 1
        L >>= 1; R >>= 1; v <<= 1
    for i in ids:
        data[i-1] = segfunc(data[2*i-1], data[2*i])

def query(l, r):
    propagates(*gindex(l, r))
    L = N0 + l; R = N0 + r

    s = 0
    while L < R:
        if R & 1:
            R -= 1
            s = segfunc(s, data[R-1])
        if L & 1:
            s = segfunc(s, data[L-1])
            L += 1
        L >>= 1; R >>= 1
    return s

update(0,N,1)
MOD = 998244353
for i in range(Q):
    l, r, d = map(int, input().split())
    update(l-1, r, d)

tt = 1
R = 0
for i in range(N-1, -1, -1):
    c = query(i, i+1)
    R = (R + c*tt) % MOD
    tt = tt*10%MOD
print(R)


Fixed submission:
import sys
input = sys.stdin.readline
class LazySegmentTree():
    def __init__(self, n, op, e, mapping, composition, id):
        self.n = n
        self.op = op
        self.e = e
        self.mapping = mapping
        self.composition = composition
        self.id = id
        self.log = (n - 1).bit_length()
        self.size = 1 << self.log
        self.d = [e] * (2 * self.size)
        self.lz = [id] * (self.size)

    def update(self, k):
#        print(self.d)
        self.d[k] = self.op(self.d[2 * k], self.d[2 * k + 1])

    def all_apply(self, k, f):
        self.d[k] = self.mapping(f, self.d[k])
        if k < self.size:
            self.lz[k] = self.composition(f, self.lz[k])

    def push(self, k):
        self.all_apply(2 * k, self.lz[k])
        self.all_apply(2 * k + 1, self.lz[k])
        self.lz[k] = self.id

    def build(self, arr):
        #assert len(arr) == self.n
        for i, a in enumerate(arr):
            self.d[self.size + i] = a
        for i in range(1, self.size)[::-1]:
            self.update(i)

    def set(self, p, x):
        #assert 0 <= p < self.n
        p += self.size
        for i in range(1, self.log + 1)[::-1]:
            self.push(p >> i)
        self.d[p] = x
        for i in range(1, self.log + 1):
            self.update(p >> i)

    def get(self, p):
        #assert 0 <= p < self.n
        p += self.size
        for i in range(1, self.log + 1):
            self.push(p >> i)
        return self.d[p]

    def prod(self, l, r):
        #assert 0 <= l <= r <= self.n
        if l == r: return self.e
        l += self.size
        r += self.size
        for i in range(1, self.log + 1)[::-1]:
            if ((l >> i) << i) != l: self.push(l >> i)
            if ((r >> i) << i) != r: self.push(r >> i)
        sml = smr = self.e
        while l < r:
            if l & 1:
                sml = self.op(sml, self.d[l])
                l += 1
            if r & 1:
                r -= 1
                smr = self.op(self.d[r], smr)
            l >>= 1
            r >>= 1
        return self.op(sml, smr)

    def all_prod(self):
        return self.d[1]

    def apply(self, p, f):
        #assert 0 <= p < self.n
        p += self.size
        for i in range(1, self.log + 1)[::-1]:
            self.push(p >> i)
        self.d[p] = self.mapping(f, self.d[p])
        for i in range(1, self.log + 1):
            self.update(p >> i)

    def range_apply(self, l, r, f):
        #assert 0 <= l <= r <= self.n
        if l == r: return
        l += self.size
        r += self.size
        for i in range(1, self.log + 1)[::-1]:
            if ((l >> i) << i) != l: self.push(l >> i)
            if ((r >> i) << i) != r: self.push((r - 1) >> i)
        l2 = l
        r2 = r
        while l < r:
            if l & 1:
                self.all_apply(l, f)
                l += 1
            if r & 1:
                r -= 1
                self.all_apply(r, f)
            l >>= 1
            r >>= 1
        l = l2
        r = r2
        for i in range(1, self.log + 1):
            if ((l >> i) << i) != l: self.update(l >> i)
            if ((r >> i) << i) != r: self.update((r - 1) >> i)

    def max_right(self, l, g):
        #assert 0 <= l <= self.n
        #assert g(self.e)
        if l == self.n: return self.n
        l += self.size
        for i in range(1, self.log + 1)[::-1]:
            self.push(l >> i)
        sm = self.e
        while True:
            while l % 2 == 0: l >>= 1
            if not g(self.op(sm, self.d[l])):
                while l < self.size:
                    self.push(l)
                    l = 2 * l
                    if g(self.op(sm, self.d[l])):
                        sm = self.op(sm, self.d[l])
                        l += 1
                return l - self.size
            sm = self.op(sm, self.d[l])
            l += 1
            if (l & -l) == l: return self.n

    def min_left(self, r, g):
        #assert 0 <= r <= self.n
        #assert g(self.e)
        if r == 0: return 0
        r += self.size
        for i in range(1, self.log + 1)[::-1]:
            self.push((r - 1) >> i)
        sm = self.e
        while True:
            r -= 1
            while r > 1 and r % 2: r >>= 1
            if not g(self.op(self.d[r], sm)):
                while r < self.size:
                    self.push(r)
                    r = 2 * r + 1
                    if g(self.op(self.d[r], sm)):
                        sm = self.op(self.d[r], sm)
                        r -= 1
                return r + 1 - self.size
            sm = self.op(self.d[r], sm)
            if (r & -r) == r: return 0

mod = 998244353
N,Q = map(int,input().split())
O = [1]*(N+1)
P = [1]*(N+1)
c=kk=1
for i in range(1, N+1):
    O[i] = c
    kk=kk*10%mod
    P[i] = kk
    c=(c+kk)%mod

def op(x, y):
    return ((P[y[1]]*x[0] + y[0]) % mod, x[1]+y[1])

def mapping(p, x):
    if p:
        return (O[x[1]] * p % mod, x[1])
    return x

def composition(p, q):
    if p == 0: return q
    return p

res = [(1, 1)]*N
LST = LazySegmentTree(N,op,(0, 0),mapping,composition,0)
LST.build(res)
for _ in range(Q):
    l,r,D = map(int,input().split())
    LST.range_apply(l-1,r,D)
    print(LST.all_prod()[0])