uva 11991 Easy Problem from Rujia Liu

原题链接：http://acm.hust.edu.cn/vjudge/problem/viewProblem.action?id=18696 
方法很多，我用的是快排+二分，练习一下stl lower_bound这个函数。。。

 1 #include<algorithm>
 2 #include<iostream>
 3 #include<cstdlib>
 4 #include<cstring>
 5 #include<cstdio>
 6 using std::sort;
 7 using std::lower_bound;
 8 const int Max_N = 100010;
 9 struct node {
10     int v, id;
11 }rec[Max_N];
12 int arr[Max_N];
13 bool cmp(node &a, node &b) {
14     if (a.v == b.v) return a.id < b.id;
15     return a.v < b.v;
16 }
17 int main() {
18 #ifdef LOCAL
19     freopen("in.txt", "r", stdin);
20     freopen("out.txt", "w+", stdout);
21 #endif
22     int n, m, a, b, pos;
23     while (~scanf("%d %d", &n, &m)) {
24         for (int i = 0; i < n; i++) {
25             scanf("%d", &rec[i].v);
26             rec[i].id = i + 1;
27         }
28         sort(rec, rec + n, cmp);
29         for (int i = 0; i < n; i++) arr[i] = rec[i].v;
30         while (m--) {
31             scanf("%d %d", &a, &b);
32             pos = lower_bound(arr, arr + n, b) - arr;
33             node &k = rec[pos + a - 1];
34             if (k.v == b) printf("%d\n", k.id);
35             else puts("0");
36         }
37     }
38     return 0;
39 }
View Code

 

posted @ 2015-05-16 17:21  GadyPu  阅读(135)  评论(0)  编辑  收藏  举报