HDU 1160 FatMouse's Speed (dp, 最长子序列）

HDU 1160

dp[i]表示以第i个结尾的最长序列的长度。

参考博客：http://www.cnblogs.com/kuangbin/archive/2011/08/04/2127944.html

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <queue>
using namespace std;
const int MAXN = 1010;
int dp[MAXN], res[MAXN], pre[MAXN];
struct node {
	int w, s;
	int id;
};
bool cmp(node a, node b) {
	if(a.w != b.w) return a.w < b.w;
	else return a.s > b.s;
}
node mouse[MAXN];
int main() {
	int i = 1, w, s;
	while(~scanf("%d %d", &w, &s)) {
		dp[i] = 1;
		pre[i] = 0;
		mouse[i].s = s, mouse[i].w = w, mouse[i].id = i;
		i++;
	}
	int num = i - 1;
	sort(mouse + 1, mouse + num + 1, cmp);
	int j;
	int maxlen = 0, maxleni = 1;
	for(i = 1; i <= num; i++) {
		for(j = 1; j < i; j++) {
			if(mouse[j].w < mouse[i].w && mouse[j].s > mouse[i].s && dp[j] + 1 > dp[i]) {
				dp[i] = dp[j] + 1;
				pre[i] = j;
				if(dp[i] > maxlen) {
					maxlen = dp[i];
					maxleni = i;
				}
			}
		}
	}
	int t = maxleni;
	i = 0;
	while(t != 0) {
		res[i++] = t;
		t = pre[t];
	}
	printf("%d\n", i);
	while(i > 0) {
		i--;
		printf("%d\n", mouse[res[i]].id);
	}
    return 0;
}