leetcode300. Longest Increasing Subsequence 最长递增子序列

class Solution {
public:
    int lengthOfLIS(vector<int>& nums) {
        int length = nums.size();
        if(length <= 0)
            return 0;
        vector<int> result(length);
        for(int i = 0;i < length;i++)
            result[i] = 1;
        for(int i = 1;i < length;i++){
            int max_sum = 1;
            for(int j = i-1;j >= 0;j--){
                if(nums[i] > nums[j]){
                    int num = result[j] + 1;
                    if(num > max_sum)
                        max_sum = num;
                }
            }
            result[i] = max_sum;
        }
        int max = 1;
        for(int i = 0;i < length;i++){
            if(result[i] > max)
                max = result[i];
        }
        return max;
    }
};