【HDOJ】2389 Rain on your Parade

读题显然是二分图匹配，看成guest与umbrella的匹配。匈牙利果断TLE了，其实时间卡的相当紧。HK过的，750ms。

/* 2389 */
#include <iostream>
#include <string>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <vector>
#include <algorithm>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstring>
#include <climits>
#include <cctype>
using namespace std;

typedef struct {
    int v, next;
} Edge_t;

const int maxn = 3005;

Edge_t E[maxn*maxn];
int head[maxn], L;
int dx[maxn], dy[maxn];
int xpre[maxn], ypre[maxn];
int gx[maxn], gy[maxn], gs[maxn];
bool visit[maxn];
int rt, n, m;
int ans, dis;
    
void init() {
    L = 0;
    memset(head, -1, sizeof(head));
    memset(xpre, -1, sizeof(xpre));
    memset(ypre, -1, sizeof(ypre));
}

void addEdge(int u, int v) {
    E[L].v = v;
    E[L].next = head[u];
    head[u] = L++;
}

bool bfs() {
    int i, j, k;
    int u, v;
    queue<int> Q;
    
    memset(dx, -1, sizeof(dx));
    memset(dy, -1, sizeof(dy));
    dis = INT_MAX;
    
    for (i=0; i<m; ++i) {
        if (xpre[i] == -1) {
            Q.push(i);
            dx[i] = 0;
        }
    }
    
    while (!Q.empty()) {
        u = Q.front();
        Q.pop();
        if (dx[u] > dis)
            break;
        for (i=head[u]; i!=-1; i=E[i].next) {
            v = E[i].v;
            if (dy[v] == -1) {
                dy[v] = dx[u] + 1;
                if (ypre[v] == -1) {
                    dis = dy[v];
                } else {
                    dx[ypre[v]] = dy[v] + 1;
                    Q.push(ypre[v]);
                }
            }
        }
    }
    
    return dis!=INT_MAX;
}

int dfs(int u) {
    int i, v;
    // Edge_t e;
    
    for (i=head[u]; i!=-1; i=E[i].next) {
        v = E[i].v;
        if (!visit[v] && dy[v]==dx[u]+1) {
            visit[v] = true;
            if (ypre[v]!=-1 && dy[v]==dis)
                continue;
            if (ypre[v]==-1 || dfs(ypre[v])) {
                xpre[u] = v;
                ypre[v] = u;
                return 1;
            }
        }
    }
    
    return 0;
}

int HK() {
    int ret = 0;
    
    while (bfs()) {
        memset(visit, false, sizeof(visit));
        for (int i=0; i<m; ++i)
            if (xpre[i] == -1)
                ret += dfs(i);
    }
    return ret;
}

int main() {
    int i, j, k;
    int t, tt;
    int x, y;
    
    #ifndef ONLINE_JUDGE
        freopen("data.in", "r", stdin);
        freopen("data.out", "w", stdout);
    #endif
    
    scanf("%d", &tt);
    for (t=1; t<=tt; ++t) {
        scanf("%d", &rt);
        scanf("%d", &m);
        init();
        for (i=0; i<m; ++i)
            scanf("%d %d %d", &gx[i], &gy[i], &gs[i]);
        scanf("%d", &n);
        for (i=0; i<n; ++i) {
            scanf("%d %d", &x, &y);
            for (j=0; j<m; ++j) {
                dis = gs[i] * rt;
                if ((x-gx[j])*(x-gx[j])+(y-gy[j])*(y-gy[j]) <= dis*dis)
                    addEdge(j, i);
            }
        }
        ans = HK();
        printf("Scenario #%d:
%d

", t, ans);
    }
    
    #ifndef ONLINE_JUDGE
        printf("%d
", (int)clock());
    #endif
    
    return 0;
}