func_code_string: #include <bits/stdc++.h>   using namespace std;   struct A {     int a[500000];     int& operator[](const int x) { return a[x + 250000]; }   } f[2];   int a, b, k, t, m;   int main() {     scanf( %d%d%d%d , &a, &b, &k, &t);     m = 2 * k * t + 200;     f[0][a - b] = 1;     for (int i = 1; i <= t << 1; ++i) {       long long sum = 0;       for (int j = -m - k - 1; j <= -m + k - 1; ++j)         sum = (sum + f[(i & 1) ^ 1][j]) % 1000000007;       for (int j = -m; j <= m; ++j) {         sum = (sum - f[(i & 1) ^ 1][j - k - 1] + f[(i & 1) ^ 1][j + k]) %               1000000007;         f[i & 1][j] = sum;       }     }     long long ans = 0;     for (int i = 1; i <= m; ++i) ans = (ans + f[(t << 1) & 1][i]) % 1000000007;     printf( %lld n , (ans + 1000000007) % 1000000007);     return 0;   }   