leetcode(16)最接近的三数之和

最接近的三数之和

解题思路：排序+双指针

class Solution {
    public int threeSumClosest(int[] nums, int target) {
        int len = nums.length;
        Arrays.sort(nums);
        int l = 0;
        int r = 0;
        int min = Math.abs(nums[0]+nums[1]+nums[2]-target);
        int sum = nums[0]+nums[1]+nums[2];
        int temp = 0;
        int temp2 = 0;
        int flag =0;
        for(int i=0;i<len-2;i++){
            l=i+1;
            r=len-1;
            flag = 0;
            while(l<r){
                temp = nums[i]+nums[r]+nums[l];
                if(temp<target){
                    if(flag==-1){
                        if(Math.abs(temp-target)<min) {
                            min = Math.abs(temp-target);
                            sum = temp;
                        }
                        temp2 = nums[i]+nums[r+1]+nums[l];
                        if(Math.abs(temp2-target)<min){
                            min = Math.abs(temp2-target);
                            sum = temp2;
                        }
                    }
                    flag=1;
                    while(l<r&&nums[l+1]==nums[l]){
                        l++;
                    }
                    l++;
                }else if(temp>target){
                    if(flag==1){
                        if(Math.abs(temp-target)<min) {
                            min = Math.abs(temp-target);
                            sum = temp;
                        }
                        temp2 = nums[i]+nums[r]+nums[l-1];
                        if(Math.abs(temp2-target)<min){
                            min = Math.abs(temp2-target);
                            sum = temp2;
                        }
                    }
                    flag=-1;
                    while(l<r&&nums[r-1]==nums[r]){
                        r--;
                    }
                    r--;
                }else{
                    return temp;            
                }
            }
            if(flag==1){
                temp = nums[i]+nums[r]+nums[l-1];
                if(Math.abs(temp-target)<min){
                    min = Math.abs(temp-target);
                    sum = temp;
                }
            }else{
                temp = nums[i]+nums[r+1]+nums[l];
                if(Math.abs(temp-target)<min){
                    min = Math.abs(temp-target);
                    sum = temp;
                }
            }
        }
        return sum;
    }
}