pku 1631 Bridging signals nLogn效率的最长上升子序列

 

nLogn效率的最长上升子序列,第一次用二分查找

 

题目：

http://acm.pku.edu.cn/JudgeOnline/problem?id=1631

#include <stdio.h>#include <string.h>#define maxn 40001int num[maxn];//B[i]表示序列长度为i的所有序列的末尾元素的最小值int B[maxn];//opt[i]表示以第i个元素结尾的序列中的最长上升子序列的长度int opt[40001];int main(){freopen("data.txt","r",stdin);int T,n,i;scanf("%d",&T); while(T--) {scanf("%d",&n); for(i=1;i <= n;i++) scanf("%d",num + i);memset(opt,1,sizeof(opt));int s,left,right,mid;int blen = 0;int max = 0;for(i = 1;i <= n;i++){left = 1;right = blen;s = num[i];while(left <= right){mid = (left + right) / 2;if(B[mid] < s)left = mid + 1;else right = mid - 1;}opt[i] = left;B[left] = s;blen = blen < left ? left : blen;max = max < opt[i] ? opt[i] : max;}printf("%d/n",max); }return 0;}