Perfect Square

LeetCode/perfectSquare.java

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+/*
+Given an integer n, return the least number of perfect square numbers that sum to n.
+
+A perfect square is an integer that is the square of an integer; in other words, 
+it is the product of some integer with itself. For example, 1, 4, 9, and 16 are perfect squares 
+while 3 and 11 are not.
+ */
+
+class Solution {
+ public int numSquares(int n) {
+ int dp[]=new int[n+1]; //created an array of length n+1
+ dp[0]=0; //initalized 0th position with 0
+ dp[1]=1; //initialized 1st position with 1
+
+ for(int i=2;i<=n;i++) //initialized for loop from 2 to n
+ {
+ int ans=Integer.MAX_VALUE; // assume ans is the maximum value
+ for(int j=1;j*j<=i;j++) //traversing j loop as perfect square
+ {
+ int rem=i-j*j; //if remainder is remaing
+ if(dp[rem]<ans) // checking position of remainder less than ans 
+ ans=dp[rem]; //storing the ans as value at dp[rem]
+ }
+ dp[i]=ans+1; //at the end of j loop storing the ans as ans+1
+ }
+
+ return dp[n]; //returning the nth position as ans
+
+ }
+}