Commit 536455b

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Implemented the O(logN) algorithm for LIS

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Lines changed: 7 additions & 15 deletions

Original file line number	Diff line number	Diff line change
`@@ -5,22 +5,14 @@ using namespace std;`
`5`	`5`	`class Solution {`
`6`	`6`	`public:`
`7`	`7`	`int lengthOfLIS(vector<int>& nums) {`
`8`		`- vector<int> dp(nums.size(), 1);`
`9`		`- for (int i = 0; i < nums.size(); i++) {`
`10`		`- for (int j = 0; j < i; j++) {`
`11`		`- // nums[i] should be contained as the last element in subsequence.`
`12`		`- if (nums[j] < nums[i] && dp[j] + 1 > dp[i]) {`
`13`		`- dp[i] = dp[j] + 1;`
`14`		`- }`
	`8`	`+ vector<int> ans;`
	`9`	`+ for (int x : nums) {`
	`10`	`+ auto it = lower_bound(ans.begin(), ans.end(), x);`
	`11`	`+ if (it == ans.end()) {`
	`12`	`+ ans.push_back(x);`
`15`	`13`	`}`
	`14`	`+ else *it = x;`
`16`	`15`	`}`
`17`		`-`
`18`		`- int res = 0;`
`19`		`- for (int i : dp) {`
`20`		`- if (i > res) {`
`21`		`- res = i;`
`22`		`- }`
`23`		`- }`
`24`		`- return res;`
	`16`	`+ return ans.size();`
`25`	`17`	`}`
`26`	`18`	`};`

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