Random

Author: gs146

Random pick with weight

@@ -0,0 +1,23 @@
+class Solution {
+public:
+    vector<int> v;
+    Solution(vector<int>& w) 
+    {
+        v.push_back(w[0]);
+        for(int i=1;i<w.size();i++){
+            v.push_back(v[i-1]+w[i]);        
+    }
+    }
+    
+    int pickIndex() {
+        int n= rand()%v[v.size()-1];
+        auto it=upper_bound(v.begin(),v.end(),n);
+        return it-v.begin();        
+    }
+};
+
+/**
+ * Your Solution object will be instantiated and called as such:
+ * Solution* obj = new Solution(w);
+ * int param_1 = obj->pickIndex();
+ */