UVa 100131 Is Bigger Smarter（LIS）

题意：

有N头象，找出其中体重从小到大，智商从高到底的X只，并输出。

思路：

先对于象的体重进行从小到大排序，然后对其智商进行最长下降子序列选择

#include <cstdio>

#include <cstdlib>

#include <cstring>

#include <vector>

#include <algorithm>



using namespace std;



struct Node {

    int i;

    int w, s;



    Node(int _w, int _s, int _i) : w(_w), s(_s), i(_i) { }



    friend bool operator < (const Node &a, const Node &b)

    { return a.w < b.w; }

};



vector<Node> ele;



int dp[1010], pre[1010];



int main()

{

    int w, iq;

    int id = 0;

    while (scanf("%d %d", &w, &iq) != EOF)

    {

        ele.push_back(Node(w, iq, id + 1));

        ++id;

    }

    ele.push_back(Node(0, 0, 0));



    sort(&ele[0], &ele[id]);

    

    memset(dp, 0, sizeof(dp));

    memset(pre, 0, sizeof(pre));



    

    int mm, pos;



    dp[0] = 1, pre[0] = -1;

    mm = 1, pos = 0;



    for (int i = 1; i < id; ++i)

    {

        dp[i] = 1;

        for (int j = 0; j < i; ++j)

        {

            if (ele[i].s < ele[j].s && ele[i].w > ele[j].w && dp[i] <= dp[j])

                dp[i] = dp[j] + 1, pre[i] = j;



            if (mm <= dp[i])

                mm = dp[i], pos = i;

        }

    }

    vector<int> p;

    for (int i = 0; i < mm; ++i)

        p.push_back(ele[pos].i), pos = pre[pos];



    printf("%d\n", mm);

    for (int i = mm - 1; i >= 0; --i)

        printf("%d\n", p[i]);



    return 0;

}