标签:树状数组
Time Limit: 7000MS | Memory Limit: 65536K | |
Total Submissions: 45960 | Accepted: 16702 |
Description
Input
Output
Sample Input
5 9 1 0 5 4 3 1 2 3 0
Sample Output
6 0
Source
数据比较大,设置一个pos相当于离散
#include<iostream> #include<cstdio> #include<cstring> #include<algorithm> #include<cmath> #include<queue> #include<stack> #include<vector> #include<set> #include<map> #define L(x) (x<<1) #define R(x) (x<<1|1) #define MID(x,y) ((x+y)>>1) #define eps 1e-8 typedef __int64 ll; #define fre(i,a,b) for(i = a; i <b; i++) #define free(i,b,a) for(i = b; i >= a;i--) #define mem(t, v) memset ((t) , v, sizeof(t)) #define ssf(n) scanf("%s", n) #define sf(n) scanf("%d", &n) #define sff(a,b) scanf("%d %d", &a, &b) #define sfff(a,b,c) scanf("%d %d %d", &a, &b, &c) #define pf printf #define bug pf("Hi\n") using namespace std; #define INF 0x3f3f3f3f #define N 500005 int a[N],c[N]; int n; struct stud{ int pos,x; bool operator < (const stud &b)const { return x<b.x; } }f[N]; int lowbit(int x) { return x&(-x); } void update(int x) { while(x<=n) { c[x]++; x+=lowbit(x); } } int sum(int x) { int s=0; while(x) { s+=c[x]; x-=lowbit(x); } return s; } int main() { int i,j; while(sf(n),n) { for(i=1;i<=n;i++) { sf(f[i].x); f[i].pos=i; } sort(f+1,f+n+1); ll ans=0; mem(c,0); for(i=1;i<=n;i++) { ans+=sum(n)-sum(f[i].pos-1); update(f[i].pos); } pf("%I64d\n",ans); } return 0; }
POJ 2299 Ultra-QuickSort(逆序数 树状数组)
标签:树状数组
原文地址:http://blog.csdn.net/u014737310/article/details/45007669