func_code_string: #include <bits/stdc++.h>   using namespace std;   const int MAXN = 1024;   double p[MAXN][MAXN];   int a[MAXN];   int main() {     int n, m;     scanf( %d%d , &n, &m);     for (int i = 0; i < n; ++i) {       scanf( %d , a + i);       for (int j = 0; j < i; ++j) p[i][j] = a[i] > a[j], p[j][i] = 1 - p[i][j];     }     for (int x, y; m--;) {       scanf( %d%d , &x, &y), --x, --y;       for (int i = 0; i < n; ++i)         if (i != x && i != y) {           p[i][x] = p[i][y] = (p[i][x] + p[i][y]) / 2;           p[x][i] = p[y][i] = 1 - p[i][x];         }       p[x][y] = (p[x][y] + p[y][x]) / 2, p[y][x] = 1 - p[x][y];     }     double e = 0;     for (int i = 0; i < n; ++i)       for (int j = i + 1; j < n; ++j) e += p[i][j];     printf( %.16lf n , e);     return 0;   }   