Poj--2352（树状数组）
2014-09-08 15:51:22
思路：直接树状数组，这题给我的启示是：树状数组要从1开始编号，而不能从0开始，因为lowbit（0） == 0，会导致无限循环。
1 /************************************************************************* 2 > File Name: p2352.cpp 3 > Author: Nature 4 > Mail: 564374850@qq.com 5 > Created Time: Mon 08 Sep 2014 03:27:37 PM CST 6 ************************************************************************/ 7 8 #include <cstdio> 9 #include <cstring> 10 #include <cstdlib> 11 #include <cmath> 12 #include <vector> 13 #include <queue> 14 #include <iostream> 15 #include <algorithm> 16 using namespace std; 17 typedef long long ll; 18 const int INF = 1 << 29; 19 const int maxn = 32005; 20 21 int N; 22 int x,y; 23 int c[maxn + 5]; 24 int ra[15005]; 25 26 int Lowbit(int x){return x & (-x);} 27 void Update(int x,int d){while(x <= maxn){ c[x] += d,x += Lowbit(x);}} 28 int Getsum(int x){int res = 0;while(x){res += c[x],x -= Lowbit(x);}return res;} 29 30 int main(){ 31 while(scanf("%d",&N) != EOF){ 32 memset(ra,0,sizeof(ra)); 33 memset(c,0,sizeof(c)); 34 for(int i = 1; i <= N; ++i){ 35 scanf("%d%d",&x,&y); 36 ++x; 37 Update(x,1); 38 ra[Getsum(x) - 1]++; 39 } 40 for(int i = 0; i < N; ++i) printf("%d\n",ra[i]); 41 } 42 return 0; 43 } 44
