LightOJ 1155 - Power Transmission【拆點網絡流】

題目連結：http://www.lightoj.com/volume_showproblem.php?problem=1155

1~N每個點有容量限制，這樣就把每個點拆開，容量為限制的容量。

代碼：

#include <iostream>  
#include <algorithm>  
#include <set>  
#include <map>  
#include <string.h>  
#include <queue>  
#include <sstream>  
#include <stdio.h>  
#include <math.h>  
#include <stdlib.h>  

using namespace std;

const int MAXN = ;//點數的最大值
const int MAXM = ;//邊數的最大值
const int INF = ;

struct Edge
{
    int to, next, cap, flow;
}edge[MAXM];//注意是MAXM

int tol;
int head[MAXN];
int gap[MAXN], dep[MAXN], pre[MAXN], cur[MAXN];

void init()
{
    tol = ;
    memset(head, -, sizeof(head));
}
//加邊，單向圖三個參數，雙向圖四個參數
void addedge(int u, int v, int w, int rw = )
{
    edge[tol].to = v; edge[tol].cap = w; edge[tol].next = head[u];
    edge[tol].flow = ; head[u] = tol++;
    edge[tol].to = u; edge[tol].cap = rw; edge[tol].next = head[v];
    edge[tol].flow = ; head[v] = tol++;
}
//輸入參數：起點、終點、點的總數
//點的編号沒有影響，隻要輸入點的總數
int sap(int start, int end, int N)
{
    memset(gap, , sizeof(gap));
    memset(dep, , sizeof(dep));
    memcpy(cur, head, sizeof(head));
    int u = start;
    pre[u] = -;
    gap[] = N;
    int ans = ;
    while (dep[start] < N)
    {
        if (u == end)
        {
            int Min = INF;
            for (int i = pre[u]; i != -; i = pre[edge[i ^ ].to])
                if (Min > edge[i].cap - edge[i].flow)
                    Min = edge[i].cap - edge[i].flow;
            for (int i = pre[u]; i != -; i = pre[edge[i ^ ].to])
            {
                edge[i].flow += Min;
                edge[i ^ ].flow -= Min;
            }
            u = start;
            ans += Min;
            continue;
        }
        bool flag = false;
        int v;
        for (int i = cur[u]; i != -; i = edge[i].next)
        {
            v = edge[i].to;
            if (edge[i].cap - edge[i].flow && dep[v] +  == dep[u])
            {
                flag = true;
                cur[u] = pre[v] = i;
                break;
            }
        }
        if (flag)
        {
            u = v;
            continue;
        }
        int Min = N;
        for (int i = head[u]; i != -; i = edge[i].next)
            if (edge[i].cap - edge[i].flow && dep[edge[i].to] < Min)
            {
                Min = dep[edge[i].to];
                cur[u] = i;
            }
        gap[dep[u]]--;
        if (!gap[dep[u]])return ans;
        dep[u] = Min + ;
        gap[dep[u]]++;
        if (u != start) u = edge[pre[u] ^ ].to;
    }
    return ans;
}

int m, n, s, t;
int a, b, c;

int store[];

int main()
{
    int T, cases = ;
    scanf("%d", &T);
    while (T--)
    {
        init();
        scanf("%d", &n);
        for (int i = ;i <= n;i++) scanf("%d", &store[i]);
        for (int i = ;i <= n;i++) addedge(i, i + n, store[i]);

        scanf("%d", &m);
        while (m--)
        {
            scanf("%d%d%d", &a, &b, &c);
            addedge(a + n, b, c);
        }
        scanf("%d%d", &a, &b);
        while (a--)
        {
            scanf("%d", &c);
            addedge(, c, );
        }
        while (b--)
        {
            scanf("%d", &c);
            addedge(c + n,  * n+, );
        }
        int ans = sap(,  * n + ,  * n + );
        printf("Case %d: %d\n", cases++, ans);
    }
    return ;
}