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81 lines
2.1 KiB
C++
81 lines
2.1 KiB
C++
#include <cstdio>
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#include <cstring>
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const int maxn = 201, inf = 0x3f3f3f3f;
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inline int min(int a, int b) { return (a < b ? a : b); }
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struct Edge
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{
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int from, to, cap;
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Edge *next, *rev;
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Edge(int f, int t, int c) : from(f), to(t), cap(c), next(0), rev(0){};
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};
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typedef Edge *lpEdge;
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lpEdge addEdge(lpEdge *G, int from, int to, int cap)
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{
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lpEdge newEdge = new Edge(from, to, cap);
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if (G[from])
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newEdge->next = G[from];
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G[from] = newEdge;
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return newEdge;
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}
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lpEdge G[maxn], cur[maxn];
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int que[maxn], depth[maxn];
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int m, n, target;
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bool getDepth(int s, int e)
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{
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memset(depth, inf, sizeof(depth));
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int head = 0, tail = 0, x;
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que[tail++] = s;
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depth[s] = 0;
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while (head < tail)
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{
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x = que[head++];
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if (x == e)
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return true;
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for (lpEdge i = G[x]; i; i = i->next)
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if (i->cap && depth[i->to] == inf)
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que[tail++] = i->to, depth[i->to] = depth[x] + 1;
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}
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return false;
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}
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int dfs(int x, int minFlow)
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{
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if (x == target || minFlow == 0) return minFlow;
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int flow = 0, curFlow;
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for (lpEdge &i = (cur[x] ? cur[x] : cur[x] = G[x]); i; i = i->next)
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if ((depth[x] + 1 == depth[i->to]) && (curFlow = dfs(i->to, min(minFlow, i->cap))) > 0)
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{
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i->cap -= curFlow;
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i->rev->cap += curFlow;
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flow += curFlow;
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minFlow -= curFlow;
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if (minFlow == 0) break;
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}
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return flow;
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}
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int Dinic(int s, int e)
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{
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target = e;
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int ans = 0;
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while (getDepth(s, e))
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memset(cur, 0, sizeof(cur)),
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ans += dfs(s, inf);
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return ans;
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}
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int main()
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{
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lpEdge edge1, edge2;
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while (~scanf("%d%d", &m, &n))
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{
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memset(G, 0, sizeof(G));
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for (int i = 0, s, e, c; i < m; i++)
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{
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scanf("%d%d%d", &s, &e, &c);
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edge1 = addEdge(G, s, e, c);
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edge2 = addEdge(G, e, s, 0);
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edge1->rev = edge2;
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edge2->rev = edge1;
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}
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printf("%d\n", Dinic(1, n));
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}
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return 0;
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} |