HDU - 1160 FatMouse's Speed(DAG)

题目大意：给出N只老鼠的体重和速度
要求你找出最多的老鼠，这些老鼠满足体重递增，速度递减

解题思路：DAG裸题

#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
const int N = 100010;
const int INF = 0x3f3f3f3f;

struct Mouse{
    int id, weight, speed;
}mouse[N];

int dp[N], path[N];
int n = 0, id = 1;

bool cmp(const Mouse &a, const Mouse &b) {
    if (a.weight == b.weight)
        return a.speed > b.speed;
    else 
        return a.weight < b.weight;
}

void out(int mark) {
    if (path[mark] == 0) {
        printf("%d\n", mouse[mark].id);
        return ;
    }
    out(path[mark]);
    printf("%d\n", mouse[mark].id);

}
void solve(){ 
    sort(mouse, mouse + n, cmp);
    path[0] = -1;
    dp[0] = 0;
    int Max = 0, mark = 0;;

    for (int i = 1; i < n; i++)
        for (int j = 0; j < i; j++)
            if (mouse[i].weight > mouse[j].weight && mouse[i].speed < mouse[j].speed && dp[i] < dp[j] + 1) {
                dp[i] = dp[j] + 1;
                path[i] = j;
                if (dp[i] > Max) {
                    Max = dp[i];
                    mark = i;
                }
            }
    printf("%d\n", Max);
    out(mark);
}

int main() {
    while (scanf("%d%d", &mouse[n].weight, &mouse[n].speed) != EOF) {
        mouse[n++].id = id++;
    }
    mouse[n].weight = -1; mouse[n].speed = INF; mouse[n++].id = 0;
    solve();
    return 0;
}