UVA 11991 Easy Problem from Rujia Liu?

UVA_11991

    先将所有值排个序，剩下的工作就比较好办了。

#include<stdio.h>
#include<string.h>
#include<algorithm>
#define MAXD 100010
struct Point
{
    int id, v;
    bool operator < (const Point &t) const
    {
        if(v == t.v)
            return id < t.id;
        return v < t.v;    
    }
}p[MAXD];
int N, M;
void init()
{
    int i;
    for(i = 1; i <= N; i ++)
    {
        p[i].id = i;
        scanf("%d", &p[i].v);    
    }
    std::sort(p + 1, p + 1 + N);
}
int BS(int v)
{
    int min = 0, max = N, mid;
    for(;;)
    {
        mid = min + max + 1 >> 1;
        if(mid == max) break;
        if(p[mid].v >= v) max = mid;
        else min = mid;
    }
    return mid;
}
void solve()
{
    int i, k, v, t;
    for(i = 0; i < M; i ++)
    {
        scanf("%d%d", &k, &v);
        t = BS(v) + k - 1;
        if(t > N || p[t].v != v) printf("0\n");
        else printf("%d\n", p[t].id);
    }
}
int main()
{
    while(scanf("%d%d", &N, &M) == 2)
    {
        init();
        solve();    
    }
    return 0;    
}