POJ 1459 Power Network 最大流

標籤：blog   os   io   for   div   ar   amp   type   

建模不難，就讀入有點麻煩，無腦拍完dinic 1A happy～

#include <cstdio>#include <cstring>#include <cmath>#include <algorithm>#include <climits>#include <string>#include <iostream>#include <map>#include <cstdlib>#include <list>#include <set>#include <queue>#include <stack>using namespace std;typedef long long LL;const int maxn  = 105;int n,np,nc,m; //n節點數目，np電站數目，nc消費者數目，m電線int cap[maxn][maxn],s,t;        //cap 容量，s源點，t匯點int level[maxn],q[maxn * 2],qs,qe;void input() {    memset(cap,0,sizeof(cap));    s = 0; t = n + 1;    for(int i = 0;i < m;i++) {        int a,b,L; scanf(" (%d,%d)%d",&a,&b,&L);        a++; b++;        cap[a][b] = L;    }    for(int i = 0;i < np;i++) {        int a,P; scanf(" (%d)%d",&a,&P); a++;        cap[s][a] = P;    }    for(int i = 0;i < nc;i++) {        int a,C; scanf(" (%d)%d",&a,&C); a++;        cap[a][t] = C;    }    /*    printf("\n%d %d\n",s,t);    for(int i = s;i <= t;i++) {        for(int j = s;j <= t;j++) {            printf("%d ",cap[i][j]);        }        putchar(‘\n‘);    }    */}bool bfs() {    qs = qe = 0;    q[qe++] = s;    memset(level,0,sizeof(level));    level[s] = 1;    while(qs < qe) {        int v = q[qs++];        if(v == t) break;        for(int i = s;i <= t;i++) if(cap[v][i] && !level[i]) {            level[i] = level[v] + 1;            q[qe++] = i;        }    }    return level[t];}int dinic(int now,int alpha) {    int sum = 0;    if(now == t) return alpha;    for(int i = s;i <= t;i++) {        if(level[i] == level[now] + 1 && alpha && cap[now][i]) {            int ret = dinic(i,min(alpha,cap[now][i]));            cap[now][i] -= ret;            cap[i][now] += ret;            alpha -= ret;            sum += ret;        }    }    return sum;}void solve() {    int ans = 0;    while(bfs()) ans += dinic(s,INT_MAX);    printf("%d\n",ans);}int main() {    while(scanf("%d%d%d%d",&n,&np,&nc,&m) != EOF) {        input();        solve();    }    return 0;}