[CF 827D] Best Edge Wight

  1 #include <cstdio>
  2 #include <cstring>
  3 #include <cstdlib>
  4 #include <cctype>
  5 #include <algorithm>
  6 using namespace std;
  7 #define F(i, a, b) for (register int i = (a); i <= (b); i++)
  8 #define LL long long
  9 #define db double
 10 inline int rd(void) {
 11     int f = 1; char c = getchar(); for (; !isdigit(c); c = getchar()) if (c == ‘-‘) f = -1;
 12     int x = 0; for (; isdigit(c); c = getchar()) x = x*10+c-‘0‘; return x*f;
 13 }
 14 
 15 const int N = 200005;
 16 const int M = 400005;
 17 const int S = 1050000;
 18 const int W = 400000;
 19 const int MOD = (int)1e9 + 7;
 20 
 21 int n, tot, hd[N], nx[M], adj[M], key[M], Base[W + 5];
 22 LL S1; int S2, cnt[S], Max[S], Min[S];
 23 
 24 #define LC (x << 1)
 25 #define RC (x << 1 | 1)
 26 #define M ((L + R) >> 1)
 27 inline void Up(int x) {
 28     cnt[x] = cnt[LC] + cnt[RC];
 29     Max[x] = max(Max[LC], Max[RC]);
 30     Min[x] = min(Min[LC], Min[RC]);
 31 }
 32 inline void Leaf(int x, int w) {
 33     if (cnt[x] > 0)
 34         Max[x] = Min[x] = w;
 35     else Max[x] = 0, Min[x] = W+1;
 36 }
 37 void Build(int x, int L, int R) {
 38     if (L == R) {
 39         cnt[x] = Base[L];
 40         Leaf(x, L);
 41     }
 42     else {
 43         Build(LC, L, M);
 44         Build(RC, M+1, R);
 45         Up(x);
 46     }
 47 }
 48 inline void Modify(int x, int L, int R, int pos, int sign) {
 49     if (L == R) {
 50         cnt[x] += sign;
 51         Leaf(x, L);
 52         return;
 53     }
 54     pos <= M ? Modify(LC, L, M, pos, sign) : Modify(RC, M+1, R, pos, sign);
 55     Up(x);
 56 }
 57 inline int Last(int x, int L, int R, db pos) {
 58     if (pos < L) return W+1;
 59     if (pos >= R) return Max[x];
 60     if (L == R) return W+1;
 61     int tmp = Last(RC, M+1, R, pos);
 62     return tmp == W+1 ? Last(LC, L, M, pos) : tmp;
 63 }
 64 inline int Next(int x, int L, int R, db pos) {
 65     if (pos > R) return 0;
 66     if (pos <= L) return Min[x];
 67     if (L == R) return 0;
 68     int tmp = Next(LC, L, M, pos);
 69     return !tmp ? Next(RC, M+1, R, pos) : tmp;
 70 }
 71 
 72 int main(void) {
 73     #ifndef ONLINE_JUDGE
 74         freopen("tree.in", "r", stdin);
 75     #endif
 76     
 77     n = rd(), tot = 1;
 78     F(i, 1, n) {
 79         int x = rd(), y = rd(), t = rd();
 80         nx[++tot] = hd[x], hd[x] = tot, adj[tot] = y, key[tot] = t;
 81         nx[++tot] = hd[y], hd[y] = tot, adj[tot] = x, key[tot] = t;
 82         Base[t]++;
 83         S1 += t, S2 = (S2 + 1LL * t * t) % MOD;
 84     }
 85     Build(1, 1, W);
 86     
 87     int m = rd();
 88     F(i, 1, m) {
 89         int k = rd();
 90         if (k == 1) {
 91             int x = rd();
 92             for (int k = hd[x]; k > 0; k = nx[k]) {
 93                 Modify(1, 1, W, key[k], -1), S1 -= key[k], S2 = (S2 - 1LL * key[k] * key[k]) % MOD;
 94                 key[k]++, key[k^1]++;
 95                 Modify(1, 1, W, key[k], +1), S1 += key[k], S2 = (S2 + 1LL * key[k] * key[k]) % MOD;
 96             }
 97         }
 98         else {
 99             db aver = 1.0 * S1 / n;
100             int x = Last(1, 1, W, aver);
101             int y = Next(1, 1, W, aver);
102             int z = (x == W+1 ? y : !y ? x : aver-x < y-aver ? x : y);
103             
104             int tL = (S2 - 1LL * z * z) % MOD * (n - 1) % MOD;
105             int tR = (S1 % MOD - z) * (S1 % MOD - z) % MOD;
106             printf("%d\n", ((tL - tR) % MOD + MOD) % MOD);
107         }
108     }
109     
110     return 0;
111 }