Merge pull request #107 from Amit-yadav099/main

added solution of <largest rectangle in histogram>#104

C++/C++ Programs/maximumRectangleInHistrogram.cpp

@@ -0,0 +1,39 @@
+//code link https://leetcode.com/problems/largest-rectangle-in-histogram/
+
+#include<bits/stdc++.h>
+using namespace std;
+
+//this problem demonstrates the best implementation of the stack
+class Solution {
+public:
+    int largestRectangleArea(vector<int>& height) {
+        int n=height.size();
+vector<int>right(n,n);
+vector<int>left(n,-1);
+stack<int>st;
+//for Next samllest right(NSR)
+for(int i=0;i<n;i++){
+    while(!st.empty()&& height[st.top()]>height[i]){
+        right[st.top()]=i;
+        st.pop();
+    }
+    st.push(i);
+}
+
+//for Next smallest left(NSL)
+for(int i=n-1;i>=0;i--){
+    while(!st.empty() && height[st.top()]>height[i]){
+        left[st.top()]=i;
+        st.pop();
+    }
+    st.push(i);
+}
+int ans=0;
+// maximum height for the given index is the (NSR-NSL-1)
+for(int i=0;i<n;i++){
+    ans=max(ans,height[i]*(right[i]-left[i]-1));
+}
+return ans;
+}
+
+};