#include <bits/stdc++.h>   using namespace std;   const double pi = acos(0.0) * 2.0;   const long double eps = 1e-10;   const int step[8][2] = {{-1, 0}, {0, 1}, {1, 0},  {0, -1},                           {-1, 1}, {1, 1}, {1, -1}, {-1, -1}};   template <class T>   inline T abs1(T a) {     return a < 0 ? -a : a;   }   template <typename t, typename t1>   t min1(t a, t1 b) {     return a < b ? a : b;   }   template <typename t, typename... arg>   t min1(t a, arg... arr) {     return min1(a, min1(arr...));   }   template <typename t, typename t1>   t max1(t a, t1 b) {     return a > b ? a : b;   }   template <typename t, typename... arg>   t max1(t a, arg... arr) {     return max1(a, max1(arr...));   }   inline int jud(double a, double b) {     if (abs(a) < eps && abs(b) < eps)       return 0;     else if (abs1(a - b) / abs1(a) < eps)       return 0;     if (a < b) return -1;     return 1;   }   template <typename t>   inline int jud(t a, t b) {     if (a < b) return -1;     if (a == b) return 0;     return 1;   }   template <typename it, typename t1>   inline int find(t1 val, it a, int na, bool f_small = 1, bool f_lb = 1) {     int be = 0, en = na - 1;     if (*a <= *(a + na - 1)) {       if (f_lb == 0)         while (be < en) {           int mid = (be + en + 1) / 2;           if (jud(*(a + mid), val) != 1)             be = mid;           else             en = mid - 1;         }       else         while (be < en) {           int mid = (be + en) / 2;           if (jud(*(a + mid), val) != -1)             en = mid;           else             be = mid + 1;         }       if (f_small && jud(*(a + be), val) == 1) be--;       if (!f_small && jud(*(a + be), val) == -1) be++;     } else {       if (f_lb)         while (be < en) {           int mid = (be + en + 1) / 2;           if (jud(*(a + mid), val) != -1)             be = mid;           else             en = mid - 1;         }       else         while (be < en) {           int mid = (be + en) / 2;           if (jud(*(a + mid), val) != 1)             en = mid;           else             be = mid + 1;         }       if (!f_small && jud(*(a + be), val) == -1) be--;       if (f_small && jud(*(a + be), val) == 1) be++;     }     return be;   }   template <class T>   inline T lowb(T num) {     return num & (-num);   }   inline int bitnum(unsigned int nValue) { return __builtin_popcount(nValue); }   inline int bitnum(int nValue) { return __builtin_popcount(nValue); }   inline int bitnum(unsigned long long nValue) {     return __builtin_popcount(nValue) + __builtin_popcount(nValue >> 32);   }   inline int bitnum(long long nValue) {     return __builtin_popcount(nValue) + __builtin_popcount(nValue >> 32);   }   inline int bitmaxl(unsigned int a) {     if (a == 0) return 0;     return 32 - __builtin_clz(a);   }   inline int bitmaxl(int a) {     if (a == 0) return 0;     return 32 - __builtin_clz(a);   }   inline int bitmaxl(unsigned long long a) {     int temp = a >> 32;     if (temp) return 32 - __builtin_clz(temp) + 32;     return bitmaxl(int(a));   }   inline int bitmaxl(long long a) {     int temp = a >> 32;     if (temp) return 32 - __builtin_clz(temp) + 32;     return bitmaxl(int(a));   }   long long pow(long long n, long long m, long long mod = 0) {     if (m < 0) return 0;     long long ans = 1;     long long k = n;     while (m) {       if (m & 1) {         ans *= k;         if (mod) ans %= mod;       }       k *= k;       if (mod) k %= mod;       m >>= 1;     }     return ans;   }   template <class t1, class t2>   inline void add(t1 &a, t2 b, int mod = -1) {     if (mod == -1) mod = 1000000007;     a += b;     while (a >= mod) a -= mod;     while (a < 0) a += mod;   }   template <class t>   void output1(t arr) {     for (int i = 0; i < (int)arr.size(); i++) cerr << arr[i] <<    ;     cerr << endl;   }   template <class t>   void output2(t arr) {     for (int i = 0; i < (int)arr.size(); i++) output1(arr[i]);   }   const int maxn = 100100;   struct edge {     int to, nxt, val;   } e[maxn * 2];   int head[maxn], le;   int fa[maxn], anc[maxn], sz[maxn], hv[maxn], deep[maxn], loc[maxn];   int orig[maxn], lorig;   int n, nq;   int f[maxn];   pair<int, int> st[2][maxn];   int lst[2];   int ans[maxn];   struct node {     int a, b, cate;     int yul;     bool operator<(const node &a) const {       if (yul == a.yul) return cate < a.cate;       return yul < a.yul;     }   } arr[maxn * 2];   int larr;   struct segment_node {     int be, en;     int sumv, lef, rig;     bool flag;   };   struct segment_tree {     int l;     segment_node tree[maxn * 4];     inline int gleft(int no) { return no << 1; }     inline int gright(int no) { return (no << 1) + 1; }     inline int gfa(int no) { return no >> 1; }     inline segment_tree() { l = 0; }     void build(int no, int l, int r, int orig = 0, int *a = NULL) {       if (l > r) r = l;       if (l == r) {         tree[no].be = tree[no].en = l;         tree[no].sumv = 0;         tree[no].lef = tree[no].rig = 0;         tree[no].flag = 0;         return;       }       tree[no].be = l;       tree[no].en = r;       int mid = (l + r) / 2;       build(gleft(no), l, mid, orig, a);       build(gright(no), mid + 1, r, orig, a);       tree[no].sumv = 0;       tree[no].lef = tree[no].rig = 0;     }     inline void pushup(segment_node *no, segment_node *nl, segment_node *nr) {       if (nl->flag && nr->flag) {         no->lef = no->rig = nr->lef + nl->rig;         no->sumv = 0;         no->flag = 1;         return;       }       if (nl->flag && nl->lef == 0) {         memcpy(no, nr, sizeof(segment_node));         return;       }       if (nr->flag && nr->lef == 0) {         memcpy(no, nl, sizeof(segment_node));         return;       }       no->flag = 0;       if (nl->flag) {         no->lef = nr->lef + nl->rig;         no->rig = nr->rig;         no->sumv = nr->sumv;         return;       }       if (nr->flag) {         no->lef = nl->lef;         no->rig = nl->rig + nr->lef;         no->sumv = nl->sumv;         return;       }       no->lef = nl->lef;       no->rig = nr->rig;       no->sumv = nl->sumv + nr->sumv + f[nl->rig + nr->lef];     }     void down(int loc, int no) {       if (loc <= tree[no].be && loc >= tree[no].en) {         tree[no].rig = tree[no].lef = 1;         tree[no].flag = 1;         tree[no].sumv = 0;         return;       }       int mid = (tree[no].be + tree[no].en) >> 1;       if (loc <= mid)         down(loc, gleft(no));       else         down(loc, gright(no));       pushup(tree + no, tree + gleft(no), tree + gright(no));     }     void getsum(int l, int r, int no, int pp1) {       if (l > r) return;       int pp2 = pp1 + 100;       if (l <= tree[no].be && r >= tree[no].en) {         pushup(tree + pp2, tree + pp1, tree + no);         tree[pp1] = tree[pp2];         return;       }       int mid = (tree[no].be + tree[no].en) >> 1;       if (r >= tree[no].be && l <= mid) getsum(l, r, gleft(no), pp1);       if (r >= mid + 1 && l <= tree[no].en) getsum(l, r, gright(no), pp1);     }   } sgt;   void dfs(int no) {     sz[no] = 1;     hv[no] = -1;     for (int i = head[no]; i != -1; i = e[i].nxt)       if (e[i].to != fa[no]) {         fa[e[i].to] = no;         deep[e[i].to] = deep[no] + 1;         dfs(e[i].to);         sz[no] += sz[e[i].to];         if (hv[no] == -1 || sz[hv[no]] < sz[e[i].to]) hv[no] = e[i].to;       }   }   void dfs1(int no) {     orig[lorig] = no;     loc[no] = lorig++;     if (hv[no] != -1) {       anc[hv[no]] = anc[no];       dfs1(hv[no]);     }     for (int i = head[no]; i != -1; i = e[i].nxt)       if (e[i].to != fa[no] && e[i].to != hv[no]) {         anc[e[i].to] = e[i].to;         dfs1(e[i].to);       }   }   void addedge(int a, int b, int c) {     e[le].to = b;     e[le].nxt = head[a];     e[le].val = c;     head[a] = le++;   }   int main() {     ios_base::sync_with_stdio(0);     memset(head, -1, sizeof(head));     scanf( %d%d , &n, &nq);     for (int i = 1; i < n; i++) scanf( %d , f + i);     for (int i = 0; i < n - 1; i++) {       int a, b, c;       scanf( %d%d%d , &a, &b, &c);       a--;       b--;       addedge(a, b, c);       addedge(b, a, c);       arr[i].a = a;       arr[i].b = b;       arr[i].yul = -c;       arr[i].cate = -(i + 1);     }     sgt.build(1, 0, n);     dfs(0);     dfs1(0);     for (int i = 0; i < nq; i++) {       scanf( %d%d%d , &arr[i + n - 1].a, &arr[i + n - 1].b, &arr[i + n - 1].yul);       arr[i + n - 1].cate = i;       arr[i + n - 1].a--;       arr[i + n - 1].b--;       arr[i + n - 1].yul = -arr[i + n - 1].yul;     }     sort(arr, arr + nq + n - 1);     for (int i = 0; i < nq + n - 1; i++) {       if (arr[i].cate < 0) {         int no = arr[i].a;         if (deep[arr[i].b] > deep[no]) no = arr[i].b;         sgt.down(loc[no], 1);       } else {         int a = arr[i].a, b = arr[i].b;         int l = 0;         lst[0] = lst[1] = 0;         while (anc[a] != anc[b]) {           int no = a, cate = 0;           if (deep[anc[a]] < deep[anc[b]]) {             no = b;             cate = 1;           }           st[cate][lst[cate]++] = make_pair(loc[anc[no]], loc[no]);           l += abs(loc[anc[no]] - loc[no]) + 1;           if (deep[anc[a]] < deep[anc[b]])             b = fa[anc[no]];           else             a = fa[anc[no]];         }         if (a != b) {           if (deep[a] > deep[b])             st[0][lst[0]++] = make_pair(loc[b] + 1, loc[a]);           else             st[1][lst[1]++] = make_pair(loc[a] + 1, loc[b]);           l += abs(deep[a] - deep[b]);         }         int ff1 = 400000, ff2 = ff1 + 1, ff3 = ff1 + 2;         sgt.tree[ff1].rig = sgt.tree[ff1].lef = sgt.tree[ff1].sumv = 0;         sgt.tree[ff1].flag = 1;         sgt.tree[ff2].rig = sgt.tree[ff2].lef = sgt.tree[ff2].sumv = 0;         sgt.tree[ff2].flag = 1;         for (int i = lst[0] - 1; i >= 0; i--)           sgt.getsum(st[0][i].first, st[0][i].second, 1, ff1);         for (int i = lst[1] - 1; i >= 0; i--)           sgt.getsum(st[1][i].first, st[1][i].second, 1, ff2);         swap(sgt.tree[ff1].lef, sgt.tree[ff1].rig);         sgt.pushup(sgt.tree + ff3, sgt.tree + ff1, sgt.tree + ff2);         int rans = sgt.tree[ff3].sumv + f[sgt.tree[ff3].lef];         if (!sgt.tree[ff3].flag) rans += f[sgt.tree[ff3].rig];         ans[arr[i].cate] = rans;       }     }     for (int i = 0; i < nq; i++) printf( %d n , ans[i]);     return 0;   }