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Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 16948 Accepted Submission(s): 10292
#include <iostream> #include <stdio.h> #include <string.h> #include <stack> #include <vector> #include <algorithm> using namespace std; const int N = 5005; int a[N],b[N],c[N],n; int lowbit(int x){ return x&(-x); } void update(int idx,int v){ for(int i=idx;i<=n;i+=lowbit(i)){ c[i]+=v; } } int getsum(int idx){ int sum = 0; for(int i=idx;i>=1;i-=lowbit(i)){ sum+=c[i]; } return sum; } int main() { while(scanf("%d",&n)!=EOF){ for(int i=1;i<=n;i++){ scanf("%d",&a[i]); a[i]++; } memset(c,0,sizeof(c)); /* for(int i=1;i<=n;i++){ int id = 1; for(int j=i;j<=n;j++){ b[id++]=a[j]; } for(int j=1;j<i;j++){ b[id++]=a[j]; } int cnt = 0; for(int j=1;j<=n;j++){ update(b[j],1); cnt+=j-getsum(b[j]); } res = min(res,cnt); }*/ long long cnt = 0; for(int i=1;i<=n;i++){ update(a[i],1); cnt+=i-getsum(a[i]); } long long res = cnt; for(int i=1;i<=n;i++){ cnt = cnt+(n-a[i])-(a[i]-1); res = min(res,cnt); } printf("%lld\n",res); } return 0; }
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原文地址:http://www.cnblogs.com/liyinggang/p/5655478.html