func_code_string: #include <bits/stdc++.h>   using namespace std;   int cnt2 = 0;   int en = 0;   struct Dinic {     static const int MXN = 100000;     struct Edge {       int v, f, re;       Edge(int a, int b, int c) : v(a), f(b), re(c) {}     };     int n, s, t, level[MXN];     vector<Edge> E[MXN];     void init(int _n, int _s, int _t) {       n = _n;       s = _s;       t = _t;       for (int i = 0; i <= n; i++) E[i].clear();     }     void add_edge(int u, int v, int f, int flag = 0) {       en += 2;       if (flag) {         E[u].push_back(Edge(v, f, E[v].size()));         E[v].push_back(Edge(u, f, E[u].size() - 1));       } else {         E[u].push_back(Edge(v, f, E[v].size()));         E[v].push_back(Edge(u, 0, E[u].size() - 1));       }     }     bool BFS() {       memset(level, -1, sizeof(level));       queue<int> que;       que.push(s);       level[s] = 0;       while (!que.empty()) {         int u = que.front();         que.pop();         for (auto &it : E[u]) {           cnt2++;           if (it.f > 0 && level[it.v] == -1) {             level[it.v] = level[u] + 1;             que.push(it.v);           }         }       }       return level[t] != -1;     }     int DFS(int u, int nf) {       if (u == t) return nf;       int res = 0;       for (auto &it : E[u]) {         cnt2++;         if (it.f > 0 && level[it.v] == level[u] + 1) {           int tf = DFS(it.v, min(nf, it.f));           res += tf;           nf -= tf;           it.f -= tf;           E[it.v][it.re].f += tf;           if (nf == 0) return res;         }       }       if (!res) level[u] = -1;       return res;     }     int flow(int res = 0) {       while (BFS()) {         res += DFS(s, 2147483647);       }       return res;     }   } flow;   int vis[100005];   bool dfs(int first) {     if (vis[first]) return false;     if (first == 0) return true;     vis[first] = 1;     for (auto &it : flow.E[first]) {       cnt2++;       if (it.f && dfs(it.v)) {         it.f--;         flow.E[it.v][it.re].f++;         return true;       }     }     return false;   }   bool dfs2(int first) {     if (vis[first]) return false;     if (first == flow.t) return true;     vis[first] = 1;     for (auto &it : flow.E[first]) {       cnt2++;       if (it.f && dfs2(it.v)) {         it.f--;         flow.E[it.v][it.re].f++;         return true;       }     }     return false;   }   void solve() {     int n;     scanf( %d , &n);     int a[205][205];     flow.init(n * n * 2 + 2, 0, n * n * 2 + 1);     int X[4] = {0, 0, -1, 1};     int Y[4] = {1, -1, 0, 0};     for (int i = 0; i < n; i++) {       for (int j = 0; j < n; j++) {         scanf( %d , &a[i][j]);       }     }     for (int i = 0; i < n; i++) {       for (int j = 0; j < n; j++) {         if (a[i][j] != -1) {           flow.add_edge(i * n + j + 1, i * n + j + n * n + 1, 1000000, 1);           for (int k = 0; k < 4; k++) {             int first = X[k] + i, second = Y[k] + j;             if (first >= 0 && first < n && second >= 0 && second < n &&                 a[first][second] != -1 &&                 (a[i][j] == 0 || a[first][second] == 0)) {               flow.add_edge(i * n + j + 1, first * n + second + n * n + 1, 1);             }           }         }       }     }     vector<pair<int, pair<int, int> > > v;     for (int i = 1; i < n - 1; i++) {       v.push_back(make_pair(a[0][i], make_pair(0, i)));       flow.add_edge(n * n + i + 1, n * n * 2 + 1, 1);       v.push_back(make_pair(a[n - 1][i], make_pair(n - 1, i)));       flow.add_edge(n * n + i + (n - 1) * n + 1, n * n * 2 + 1, 1);       v.push_back(make_pair(a[i][0], make_pair(i, 0)));       flow.add_edge(n * n + i * n + 1, n * n * 2 + 1, 1);       v.push_back(make_pair(a[i][n - 1], make_pair(i, n - 1)));       flow.add_edge(n * n + i * n + n - 1 + 1, n * n * 2 + 1, 1);     }     long long ans = 0;     for (int i = 0; i < n - 1; i++) {       ans += abs(a[0][i + 1] - a[0][i]);       ans += abs(a[i][0] - a[i + 1][0]);       ans += abs(a[n - 1][i] - a[n - 1][i + 1]);       ans += abs(a[i][n - 1] - a[i + 1][n - 1]);     }     sort(v.begin(), v.end());     long long now = 0;     long long last = 0;     int tot = 0;     int cnt = 0;     for (auto it : v) {       fill(vis, vis + 100005, 0);       while (dfs2(0)) {         now++;         fill(vis, vis + 100005, 0);       }       ans += now * (it.first - last);       last = it.first;       int first = it.second.first * n + it.second.second + 1;       flow.add_edge(0, first, 1);       for (auto &it : flow.E[first + n * n]) {         if (it.v == n * n * 2 + 1) {           if (it.f == 1) {             it.f = 0;           } else {             flow.E[it.v][it.re].f = 0;             now--;             fill(vis, vis + 100005, 0);             dfs(first + n * n);           }         }       }     }     printf( %lld n , ans);   }   int main() {     int t = 1;     while (t--) {       solve();     }   }   