題目

1054 The Dominant Color（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 strictly dominant color takes more than half of the total area. Now given an image of resolution M by N (for example, 800×600), 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

題解

#include<iostream>
#include<map>
using namespace std;//1不在，加進去，計數/2直接用陣列a[][]=次數
int main(){
  int m,n;
  scanf
 
("%d %d",&m,&n);
  map<int,int> arr;
  int half=m*n/2;
  for(int i=0;i<n;i++){
    for(int j=0;j<m;j++){
      int num;
      //cin>>num;
      scanf("%d",&num);
      arr[num]++;//temp的次數加1
      if(arr[num]>half){
        printf("%d",num);
        return 0;
      }
    }
  }
  return 0;
}

本題主要是STL中Map的使用。
問題主要在於，被替換掉的註釋部分，用cin則執行超時。至於為何還有待思考一下。