题解 | #数组中重复的数字#

#include <vector>
class Solution {
public:


    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param numbers int整型vector 
     * @return int整型
     */
    int duplicate(vector<int>& numbers) {
        // write code here

        // for each
        for (int i = 0; i < numbers.size(); i++) {

            // get value 
            int value = numbers.at(i);

            // if value equals index, continue
            if (i == value) {
                continue;
            }

            // if value equals numbers[value],
            if (numbers[value] == value) {
                return value;
            } else {
			  	// swap and compare again 
                int temp = numbers[value];
                numbers[value] = value;
                numbers[i] = temp;
                i --;
            }
        }
        return -1;
    }
};