Codeforces Beta Round #25 (Div. 2 Only) A. IQ test【双标记/求给定数中唯一的奇数或偶数】

A. IQ test
time limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output

Bob is preparing to pass IQ test. The most frequent task in this test is to find out which one of the givenn numbers differs from the others. Bob observed that one number usually differs from the others in evenness. Help Bob — to check his answers, he needs a program that among the given n numbers finds one that is different in evenness.

Input

The first line contains integer n (3 ≤ n ≤ 100) — amount of numbers in the task. The second line contains n space-separated natural numbers, not exceeding 100. It is guaranteed, that exactly one of these numbers differs from the others in evenness.

Output

Output index of number that differs from the others in evenness. Numbers are numbered from 1 in the input order.

Examples
input
5
2 4 7 8 10
output
3
input
4
1 2 1 1
output
2

【分析】:对奇偶的下标,数量都要标记,再判断哪个数多,少的那个就是唯一的奇/偶
【代码】:
#include <bits/stdc++.h>

using namespace std;
int n,a[150];
int main()
{
    int pos1=0,pos2=0;
    int f1=0,f2=0;
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        cin>>a[i];
        if(a[i]%2==0)//对奇偶的下标,数量都要标记,再判断哪个数多,少的那个就是唯一的奇/偶
        {
            pos1=i;
            f1++;
        }
        if(a[i]%2==1)//不用位运算
        {
            pos2=i;
            f2++;
        }
    }
    if(f1>f2)
        cout<<pos2<<endl;
    else
        cout<<pos1<<endl;
    return 0;
}
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posted @ 2017-12-01 10:49  Roni_i  阅读(224)  评论(0编辑  收藏  举报