func_code_string: #include <bits/stdc++.h>   using namespace std;   const int maxN = 500 + 5;   const int maxM = 100000 + 5;   inline long long read() {     long long sum = 0, f = 1;     char ch = getchar();     while (ch <  0  || ch >  9 ) {       if (ch ==  - ) f = -1;       ch = getchar();     }     while (ch >=  0  && ch <=  9 ) {       sum = sum * 10 + ch -  0 ;       ch = getchar();     }     return f * sum;   }   int dp[maxN][maxN];   char G[maxN][maxN];   const int dr[] = {1, 0};   const int dc[] = {0, 1};   int main() {     ios::sync_with_stdio(false);     int n = read(), m = read(), len = (n + m) / 2;     for (int i = 1; i <= n; i++) scanf( %s , G[i] + 1);     if (G[1][1] != G[n][m]) {       printf( 0 n );       return 0;     }     dp[1][n] = 1;     for (int k = 2; k <= len; k++) {       for (int i = k; i >= 1; i--) {         int x1 = i, y1 = 1 + k - x1;         if (x1 > n || y1 < 1 || y1 > m) continue;         for (int j = n - k + 1; j <= n; j++) {           int x2 = j, y2 = n + m - k - x2 + 1;           if (x2 < 1 || x2 > n || y2 < 1 || y2 > m)             continue;           else if (G[x1][y1] != G[x2][y2]) {             dp[x1][x2] = 0;             continue;           }           dp[x1][x2] = (dp[x1][x2] + dp[x1][x2 + 1]) % 1000000007;           dp[x1][x2] = (dp[x1][x2] + dp[x1 - 1][x2]) % 1000000007;           dp[x1][x2] = (dp[x1][x2] + dp[x1 - 1][x2 + 1]) % 1000000007;         }       }     }     int ans = 0;     if ((n + m) % 2 == 0) {       for (int x1 = 1; x1 <= len; x1++) {         int y1 = 1 + len - x1;         if (x1 >= 1 && x1 <= n && y1 >= 1 && y1 <= m)           ans = (ans + dp[x1][x1]) % 1000000007;       }     } else {       for (int x1 = 1; x1 <= len; x1++) {         int y1 = 1 + len - x1;         if (x1 < 1 || x1 > n || y1 < 1 || y1 > m) continue;         if (y1 + 1 <= m) ans = (ans + dp[x1][x1]) % 1000000007;         if (x1 + 1 <= n) ans = (ans + dp[x1][x1 + 1]) % 1000000007;       }     }     printf( %d n , ans);     return 0;   }   