[leetcode]Largest Rectangle in Histogram

class Solution {
public:
    int largestRectangleArea(vector<int> &height) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if(height.empty()) return 0;
        
        int N = height.size();
        vector<int> left(N, 0);
        vector<int> right(N, 0);
        
        stack<int> s1;
        s1.push(0);
        
        for(int i = 1; i < N; i++){
            if(height[i] > height[s1.top()]){
                left[i] = 0;
            }else{
                while(!s1.empty() && height[i] <= height[s1.top()]){
                    s1.pop();
                }
                if(s1.empty()){
                    left[i] = i;
                }else{
                    left[i] = i-s1.top()-1;
                }
            }
            s1.push(i);
        }
        
        stack<int> s2;
        s2.push(N-1);
        
        for(int i = N-2; i >= 0; i--){
            if(height[i] > height[s2.top()]){
                right[i] = 0;
            }else{
                while(!s2.empty() && height[i] <= height[s2.top()]){
                    s2.pop();
                }
                if(s2.empty()){
                    right[i] = N-i-1;
                }else{
                    right[i] = s2.top()-i-1;
                }
            }
            s2.push(i);
        }
        
        for(int i = 0; i < N; i++){
            left[i] =(left[i] + right[i] + 1) * height[i];
        }

        return *max_element(left.begin(), left.end());
        
    }
};

补充：软件开发 , C++ ,

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