1≤n,m≤100 1 \leq n, m \leq 1001≤n,m≤100
非常简单的建图,源点连仓库,仓库连商店,商店连汇点,求个最小费用最大流,第一问直接求,第二问取反再求。
#include<stdio.h>#include<algorithm>#include<string.h>#include<queue>using namespace std;const int maxm = 10005;const int maxn = 100005;const int INF = 1e9 + 7;struct node{int u, v, flow, cost, next;}edge[maxn];int dis[maxm], head[maxm], cur[maxm], pre[maxn], f[1005][1005], map[1005][1005], a[maxm], b[maxm];int s, t, n, m, cnt;void init(){cnt = 0, s = 0, t = n + m + 1;memset(head, -1, sizeof(head));}void add(int u, int v, int w, int cost){edge[cnt].u = u, edge[cnt].v = v;edge[cnt].flow = w, edge[cnt].cost = cost;edge[cnt].next = head[u], head[u] = cnt++;edge[cnt].u = v, edge[cnt].v = u;edge[cnt].flow = 0, edge[cnt].cost = -cost;edge[cnt].next = head[v], head[v] = cnt++;}int bfs(){queue<int>q;for (int i = 0;i <= 10004;i++) dis[i] = INF;memset(pre, -1, sizeof(pre));dis[s] = 0;q.push(s);int rev = 0;while (!q.empty()){int u = q.front();q.pop();for (int i = head[u];i != -1;i = edge[i].next){int v = edge[i].v;if (dis[v] > dis[u] + edge[i].cost&&edge[i].flow){dis[v] = dis[u] + edge[i].cost;pre[v] = i;q.push(v);}}}if (dis[t] == INF) return 0;return 1;}int MCMF(){int minflow, ans = 0;while (bfs()){minflow = INF;for (int i = pre[t];i != -1;i = pre[edge[i].u])minflow = min(minflow, edge[i].flow);for (int i = pre[t];i != -1;i = pre[edge[i].u]){edge[i].flow -= minflow;edge[i ^ 1].flow += minflow;}ans += minflow*dis[t];}return ans;}int main(){int i, j, k, sum;scanf("%d%d", &n, &m);init();for (i = 1;i <= n;i++){scanf("%d", &a[i]);add(s, i, a[i], 0);}for (i = 1;i <= m;i++){scanf("%d", &b[i]);add(i + n, t, b[i], 0);}for (i = 1;i <= n;i++){for (j = 1;j <= m;j++){scanf("%d", &f[i][j]);add(i, j + n, INF, f[i][j]);}}printf("%d\n", MCMF());init();for (i = 1;i <= n;i++)add(s, i, a[i], 0);for (i = 1;i <= m;i++)add(i + n, t, b[i], 0);for (i = 1;i <= n;i++)for (j = 1;j <= m;j++)add(i, j + n, INF, -f[i][j]);printf("%d\n", -MCMF());return 0;}