func_code_string: #include <bits/stdc++.h>   using namespace std;   const int INF = 1e9;   struct Edge {     int to, cap, flow;   };   struct Graph {     int n;     vector<vector<int> > e;     vector<Edge> edges;     vector<int> d, c;     Graph() {}     Graph(int _n) {       n = _n;       e.resize(n);     }     void addEdge(int from, int to, int cap) {       e[from].push_back(edges.size());       edges.push_back(Edge({to, cap, 0}));       e[to].push_back(edges.size());       edges.push_back(Edge({from, 0, 0}));     }     bool bfs() {       d.assign(n, INF);       c.assign(n, 0);       vector<int> q(n);       int qL = 0, qR = 0;       d[0] = 0;       q[qR++] = 0;       while (qL < qR) {         int v = q[qL++];         for (int i = 0; i < (int)e[v].size(); i++) {           Edge cur = edges[e[v][i]];           if (d[cur.to] > d[v] + 1 && cur.flow < cur.cap) {             d[cur.to] = d[v] + 1;             q[qR++] = cur.to;           }         }       }       return d[n - 1] != INF;     }     int dfs(int v, int flow) {       if (v == n - 1) return flow;       if (flow == 0) return 0;       for (int &i = c[v]; i < (int)e[v].size(); i++) {         Edge cur = edges[e[v][i]];         if (d[cur.to] != d[v] + 1) continue;         int pushed = dfs(cur.to, min(flow, cur.cap - cur.flow));         if (pushed > 0) {           edges[e[v][i]].flow += pushed;           edges[e[v][i] ^ 1].flow -= pushed;           return pushed;         }       }       return 0;     }     long long flow() {       long long flow = 0;       while (bfs()) {         while (int pushed = dfs(0, INF)) {           flow += pushed;         }       }       return flow;     }   };   int main() {     int n, m, h;     while (cin >> n >> h >> m) {       vector<int> l(m), r(m), x(m), c(m);       for (int i = 0; i < m; i++) {         cin >> l[i] >> r[i] >> x[i] >> c[i];         x[i]++;         l[i]--;         r[i]--;       }       Graph gr(1 + n * (h + 1) + m + 1);       int sz = gr.n;       long long sum = 0;       for (int i = 0; i < n; i++) {         for (int j = 1; j <= h; j++) {           gr.addEdge(1 + i * (h + 1) + (j - 1), 1 + i * (h + 1) + j, INF);           gr.addEdge(1 + i * (h + 1) + j, sz - 1, 2 * j - 1);           sum += 2 * j - 1;         }       }       for (int i = 0; i < m; i++) {         if (x[i] > h) continue;         for (int t = l[i]; t <= r[i]; t++) {           gr.addEdge(1 + n * (h + 1) + i, 1 + t * (h + 1) + x[i], INF);         }         gr.addEdge(0, 1 + n * (h + 1) + i, c[i]);       }       cout << sum - gr.flow() << endl;     }   }   