pat 1101. Quick Sort (25)

来源：互联网发布：黑科技软件论坛编辑：程序博客网时间：2024/04/30 11:16

https://www.patest.cn/contests/pat-a-practise/1101

参考了：

http://www.sigmainfy.com/blog/pat-advanced-1101-quick-sort.html

用了动态规划，记录每个元素左边的最大值，右边的最小值。查看当前元素是否比左边的最大大，比右边的最小小。

#include <stdio.h>#include <algorithm>#include <climits>int n, a[100001], min[100001], max, pivots[100001], np;int main(){while (scanf("%d", &n) != EOF) {for (int i = 0; i < n; i++){scanf("%d",&a[i]);}max = a[0];min[n] = INT_MAX;min[n - 1] = a[n - 1];for (int i = n-2; i >=0; i--){min[i] = std::min(min[i+1],a[i]);}np = 0;for (int i = 0; i < n; i++){if (a[i] < min[i+1] && a[i] >=max) {pivots[np++] = a[i];}max = std::max(max, a[i]);}std::sort(pivots, pivots + np);printf("%d\n",np);for (int i = 0; i < np; i++){if(i==0)printf("%d",pivots[i]);else printf(" %d", pivots[i]);}printf("\n");}    return 0;}

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