半数数字

数组中有一个数字出现的次数超过数组长度的一半，请找出这个数字。例如输入一个长度为9的数组{1,2,3,2,2,2,5,4,2}。由于数字2在数组中出现了5次，超过数组长度的一半，因此输出2。如果不存在则输出0。

class Solution {
public:
    int MoreThanHalfNum_Solution(vector<int> numbers) {
         map<int, int> map;
         for (int i : numbers)
            if (++ map[i] > numbers.size() / 2) return i;
        return 0;
    }
};

class Solution {
public:
	int MoreThanHalfNum_Solution(vector<int> numbers) {
		vector<int> v1(numbers.size(), 0);
		for (int i = 0; i<numbers.size(); i++){
			v1[numbers[i] % numbers.size()]++;
		}
		for (int i = 0; i<numbers.size(); i++){
			if (v1[numbers[i] % numbers.size()]>(numbers.size() / 2)){
				return numbers[i];
			}
		}
	}
};

class Solution {
public:
void quickSort(vector<int> & numbers, int low, int high){
		if (low<high){
			int x = low;
			int y = high;
			int ans = numbers[x];
			while (x<y){
				while (x<y&&numbers[y]>ans){
					y--;
				}
				if (x<y){
					numbers[x++] = numbers[y];
				}
				while (x<y&&numbers[x]<ans){
					x++;
				}
				if (x<y){
					numbers[y--] = numbers[x];
				}
				numbers[x] = ans;
			}
			quickSort(numbers, low, x - 1);
			quickSort(numbers, x + 1, high);
		}
	}

	int MoreThanHalfNum_Solution1(vector<int> numbers) {
		vector<int> v(numbers.size(), 0);
		quickSort(numbers, 0, numbers.size() - 1);
		int target;
		int j = 0;
		v[j]++;
		for (int i = 1; i<numbers.size(); i++){
			if (numbers[i] == numbers[0]){
				v[j]++;
				if (v[j]>numbers.size() / 2){
					target = numbers[i];
				}
			}
			else{
				j++;
			}
		}
		return target;
	}
};