A1054. The Dominant Color

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 strictly dominant 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, 2²⁴). 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

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<map>
using namespace std;
map<int, int> mp;
int main(){
    int M, N, maxColor, maxN = -1, temp;
    scanf("%d %d", &M, &N);
    for(int i = 0; i < M; i++){
        for(int j = 0; j < N; j++){
            scanf("%d", &temp);
            if(mp.count(temp) == 0){
                mp[temp] = 1;
            }else{
                mp[temp] = mp[temp] + 1;
            }
            if(mp[temp] > maxN){
                maxN = mp[temp];
                maxColor = temp;
            }
        }
    }
    printf("%d", maxColor);
    cin >> N;
    return 0;
}

总结：

1、题意：找出出现次数最多的数。 由于数字的范围很大，将其作为下标建立哈希表将会开一个超限的数组。所以使用map<int, int>。