Sort it
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 3418 Accepted Submission(s): 2478
Problem Description
You want to processe a sequence of n distinct integers by swapping two adjacent sequence elements until the sequence is sorted in ascending order. Then how many times it need.
For example, 1 2 3 5 4, we only need one operation : swap 5 and 4.
Input
The input consists of a number of test cases. Each case consists of two lines: the first line contains a positive integer n (n <= 1000); the next line contains a permutation of the n integers from 1 to n.
Output
For each case, output the minimum times need to sort it in ascending order on a single line.
Sample Input
3 1 2 3 4 4 3 2 1
Sample Output
0 6
Author
WhereIsHeroFrom
Source
ZJFC 2009-3 Programming Contest
题意,用冒泡排序的方法把n个数排成按升序排列需要几步。
#include<iostream> #include<algorithm> #include<stdio.h> #include<string.h> #include<stdlib.h> using namespace std; const int N = 1001; int n; int num[N]; int c[N]; struct node{ int x; int id; }q[N] ; bool cmp(node a,node b){ return a.x < b.x; } int lowbit(int x){ return x&(-x); } int getsum(int x){ int s = 0; while(x>0){ s += c[x]; x -= lowbit(x); } return s; } void add(int x,int y){ while(x<=n){ c[x] += y; x += lowbit(x); } } int main() { while(scanf("%d",&n)!=EOF){ memset(c,0,sizeof(c)); memset(num,0,sizeof(num)); for(int i=1;i<=n;i++){ scanf("%d",&q[i].x); q[i].id = i; } sort(q+1,q+1+n,cmp); for(int i=1;i<=n;i++){ num[q[i].id] = i; } int sum = 0; for(int i=1;i<=n;i++){ add(num[i],1); sum += getsum(n) - getsum(num[i]); } printf("%d\n",sum); } return 0; }
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