HDU 1029 Ignatius and the Princess IV

HDU 1029 Ignatius and the Princess IV

Time limit: 1000 ms
Memory limit: 32767 kB
OS: Windows

Problem Description

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“OK, you are not too bad, em… But you can never pass the next test.” feng5166 says.

“I will tell you an odd number N, and then N integers. There will be a special integer among them, you have to tell me which integer is the special one after I tell you all the integers.” feng5166 says.

“But what is the characteristic of the special integer?” Ignatius asks.

“The integer will appear at least (N+1)/2 times. If you can’t find the right integer, I will kill the Princess, and you will be my dinner, too. Hahahaha…..” feng5166 says.

Can you find the special integer for Ignatius?

Input

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The input contains several test cases. Each test case contains two lines. The first line consists of an odd integer N(1<=N<=999999) which indicate the number of the integers feng5166 will tell our hero. The second line contains the N integers. The input is terminated by the end of file.

Output

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For each test case, you have to output only one line which contains the special number you have found.

Sample Input

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5
1 3 2 3 3
11
1 1 1 1 1 5 5 5 5 5 5
7
1 1 1 1 1 1 1

Sample Output

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3
5
1

思路

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这个特殊整数出现至少(N+1)/2次，多于其他所有数的和，所以可以用ans来记录目前为止出现次数最多的数，用num记录其出现次数，如果下一个数不是ans，num就-1，否则num+1，N个数输入完后，数量依然为正数的数就是出现最多的数,也就是ans

Submit

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#include <cstdio>using namespace std;int main(){    int N, n, i;    while(~scanf("%d", &N))    {        int ans = -1, num = 0;        for(i = 0; i < N; i++)        {            scanf("%d", &n);            if(num == 0)            {                num++;                ans = n;            }            else            {                if(ans != n)                    num--;                else                    num++;            }        }        printf("%d\n", ans);    }    return 0;}