hdu4584 Building bridgesa

水题..不过我更水..用BFS爆搜结果爆栈..搞不懂原因...

后来分析了一下..其实暴力搜索也能过..复杂度n^5次方..好害怕..

去网上搜了一下大神的代码..确实吊..

分析一下原因: 感觉还是做题太少,没有足够的经验..毕竟平常人..拼不过智商.

#include <iostream>
#include <string.h>
#include <stdlib.h>
#include <algorithm>
using namespace std;
const int N = 50;
const int M = 2005;
const int INF = 0x3f3f3f3f;

struct state {
    int x, y;
}c[M], h[M];

int n, m, cntC, cntH;
char s[N];

void init () {
    cntC = cntH = 0;
    for (int i = 0; i < n; i++) {
        scanf("%s", s);

        for (int j = 0; j < m; j++) {
            if (s[j] == 'C') {
                c[cntC].x = i;
                c[cntC].y = j;
                cntC++;
            } else if (s[j] == 'H') {
                h[cntH].x = i;
                h[cntH].y = j;
                cntH++;
            }
        }
    }
}

 int Cal (int a, int b) {
    return abs(h[a].x - c[b].x) + abs(h[a].y - c[b].y);
}

bool cmp (const state& a, const state& b) {
    if (a.x != b.x) return a.x < b.x;
    return a.y < b.y;
}

void solve () {
    int ans = INF, ansC, ansH;

    sort (c, c + cntC, cmp);
    sort (h, h + cntH, cmp);
    //不用排序也能用..默认已经排好序了;
    for (int i = 0; i < cntH; i++) {
        for (int j = 0; j < cntC; j++) {
            int d = Cal(i, j);
            if (d < ans) {
                ans = d;
                ansH = i;
                ansC = j;
            }
        }
    }
    printf("%d %d %d %d
", h[ansH].x, h[ansH].y, c[ansC].x, c[ansC].y);
}

int main () {
    while (!scanf("%d%d", &n, &m), n ,m) {
        init ();
        solve ();
    }
    return 0;
}