func_code_string: #include <bits/stdc++.h>   using namespace std;   int n, a, b, k;   long long MOD = 1000000007;   long long pref[5005][2], dp[5005][2];   int main() {     ios_base::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     cin >> n >> a >> b >> k;     for (int i = 0; i < n + 5; i++) {       pref[i][0] = pref[i][1] = dp[i][0] = dp[i][1] = 0;     }     if (b < a) {       a = n + 1 - a;       b = n + 1 - b;     }     dp[a][0] = 1;     for (int i = a; i < b; i++) pref[i][0] = 1;     for (int j = 1; j <= k; j++) {       for (int i = 1; i < b; i++) {         dp[i][j % 2] =             (pref[(b + i - 1) / 2][(j - 1) % 2] - dp[i][(j - 1) % 2] + MOD) % MOD;         pref[i][j % 2] = (pref[i - 1][j % 2] + dp[i][j % 2]) % MOD;       }     }     cout << pref[b - 1][k % 2] << endl;   }   