PAT 1054 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, 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 [0,224). 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:

题意：给出一个5*3的矩阵，找出矩阵内超过矩阵内数的一半且出现次数最多的数，即24；

思路：

因为输入的数据(16777215,1*10^7)有大于int最大范围（整型的最大范围是8388608，即8*10^6）,所以这里不能用数组的散列表，应该用map作为散列表，在map中用find函数，如果找得到就次数++,找不到就说明之前不存在这个数，置为1，最后遍历map，找到次数最多的那个输出就好了

学习：

1.map的定义不需要开大小范围

2.map的遍历，for(map<类型，类型>::iterator it=map.begin();it!=map.end();it++)

3.map的key和value的访问,key:it->first,value:it->second;

代码：

//map的使用;
//题目说输入的数的范围最大是到2^24，已经超过了int的最大范围,用散列表开这么大可能会超空间，所以这里用的是map; 
#include
#include
using namespace std;
int main(){
	int n,m,num;
	scanf("%d %d",&n,&m);
	map count;
	for(int i=0;i::iterator it=count.begin();it!=count.end();it++){//迭代方式
	//for(类型::iterator it=类型.begin(),it!=类型.end();it++) 
		if(it->second>max){
			max=it->second;//it就可以代表map的一个项; 
			num=it->first;
		}
	}
	printf("%d",num);
	return 0;
}

PAT 1054 The Dominant Color

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

C/C++/C#相关栏目本月热门文章

PAT 1054 The Dominant Color

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

C/C++/C#相关栏目本月热门文章

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