func_code_string: #include <bits/stdc++.h>   using namespace std;   bool flag;   int n, a[1010], vis[2010], T;   pair<int, int> ans[5];   void read(int &x) {     char ch = getchar();     int mark = 1;     for (; ch !=  -  && (ch <  0  || ch >  9 ); ch = getchar())       ;     if (ch ==  - ) mark = -1, ch = getchar();     for (x = 0; ch >=  0  && ch <=  9 ; ch = getchar()) x = x * 10 + ch - 48;     x *= mark;   }   bool check(int step) {     for (int i = 1; i <= n; i++)       if (a[i] != i) return 0;     return 1;   }   void rev(int *a, int l, int r) {     for (int i = 0; i <= (r - l - 1) / 2; i++) swap(a[i + l], a[r - i]);   }   int expect() {     int ans = 1;     for (int i = 2; i <= n; i++)       if (abs(a[i] - a[i - 1]) != 1) ans++;     return ans;   }   void dfs(int step) {     if (check(step - 1)) {       printf( %d n , step - 1);       for (int i = step - 1; i; i--)         printf( %d %d n , ans[i].first, ans[i].second);       flag = 1;       return;     }     if (step > 3) return;     int c[1010];     for (int i = 1; i <= n; i++) {       for (int j = i + 1; j <= n; j++)         if (abs(a[i - 1] - a[j]) == 1 || abs(a[i] - a[j + 1]) == 1) {           for (int k = i; k <= j; k++) c[k] = a[k];           rev(a, i, j);           if (expect() <= (3 - step) * 2 + 1) {             ans[step] = make_pair(i, j);             dfs(step + 1);             if (flag) return;           }           for (int k = i; k <= j; k++) a[k] = c[k];         }     }   }   int main() {     read(n);     for (int i = 1; i <= n; i++) read(a[i]);     a[n + 1] = n + 1;     dfs(1);     return 0;   }   