Create Russian-doll-envelops.cpp

Author: sayantann11

20. Dynamic Programming/Russian-doll-envelops.cpp

@@ -0,0 +1,21 @@
+int Solution::solve(vector < vector < int > > & A) {
+    vector < pair < int, int > > v;
+    int n = A.size();
+    for (int i = 0; i < n; i++)
+        v.push_back({A[i][0], -A[i][1]});
+
+    // sort the vector envelope in increasing order of heights
+    sort(v.begin(), v.end());
+    int dp[n];
+    dp[0] = 1;
+
+    //Find the longest increasing subsequence based on second element of v[i]
+    for (int i = 1; i < n; i++) {
+        dp[i] = 1;
+        for (int j = i - 1; j >= 0; j--) {
+            if (v[j].first < v[i].first and v[j].second > v[i].second)
+                dp[i] = max(dp[i], dp[j] + 1);
+        }
+    }
+    return *max_element(dp, dp + n);
+}