PAT 1054 The Dominant Color[简单][运行超时的问题]

1054 The Dominant Color (20)（20 分）

Behind the scenes in the computer's memory, color is always talked about as a series of 24 bits of information for each pixel. In an image, the color with the largest proportional area is called the dominant color. A strictlydominant color takes more than half of the total area. Now given an image of resolution M by N (for example, 800x600), you are supposed to point out the strictly dominant color.

Input Specification:

Each input file contains one test case. For each case, the first line contains 2 positive numbers: M (<=800) and N (<=600) which are the resolutions of the image. Then N lines follow, each contains M digital colors in the range [0, 2^24^). It is guaranteed that the strictly dominant color exists for each input image. All the numbers in a line are separated by a space.

Output Specification:

For each test case, simply print the dominant color in a line.

Sample Input:

5 3
0 0 255 16777215 24
24 24 0 0 24
24 0 24 24 24

Sample Output:

24

 题目大意：计算矩阵中出现次数超过半数的数字，数字范围是1-2^24.

 //一开始我的提交是这样的，牛客网上可以通过，但是pat上运行测试点3超时。

#include <iostream>
#include<stdio.h>
#include<map>
using namespace std;
map<int,int> mp;
int main() {
    int m,n,pix;
    int mx=0,mpx;
    cin>>m>>n;
    for(int i=0;i<n;i++)
    for(int j=0;j<m;j++){
        cin>>pix;
        if(mp[pix]==0)
            mp[pix]=1;
        else
            mp[pix]++;
        if(mp[pix]>mx){
            mpx=pix;
            mx=mp[pix];
        }
    }
    cout<<mpx;
    return 0;
}

1.参考了大佬的代码，发现大佬是直接判断如果出现超过半数，那么就直接Return 0;

2.修改return 0;之后提交仍是超时，就将mp==0去掉，直接出现就mp[pix]++;

3.提交之后还是超时，以为是数据的问题，改为map<long,int>还是不行；

4.最终将cin改为scanf即可，数据量大的时候cin读入会超时啊！

最终AC代码如下:

#include <iostream>
#include<stdio.h>
#include<map>
using namespace std;
map<int,int> mp;
int main() {
    int m,n;
    int pix;
    scanf("%d %d",&m,&n);
    int len=m*n/2;
    for(int i=0;i<n;i++)
    for(int j=0;j<m;j++){
        scanf("%d",&pix);
        mp[pix]++;
        if(mp[pix]>len){
           printf("%d",pix);
           return 0;
        }
    }

    return 0;
}

//第一次体会到，cin真的会超时。