3Sum
解题思路
此题主要是使用了二分查找的变形
代码
class Solution {
public:
vector<vector<int>> threeSum(vector<int>& nums) {
vector<vector<int>> result;
sort(nums.begin(), nums.end());
int len = nums.size();
for(int i = 0; i < len; i++) {
int a, b, c;
a = nums[i];
if(i > 0 && nums[i - 1] == a) continue;
if(a > 0) break;
int st = i + 1;
int en = len - 1;
while(st < en) {
b = nums[st];
c = nums[en];
int t = a + b + c;
if(t == 0) {
result.push_back({a, b, c});
while(st < en && nums[st] == b) st++;
while(st < en && nums[en] == c) en--;
} else if(t > 0) {
en--;
} else {
st++;
}
}
}
return result;
}
};
