Wednesday, June 30, 2021

LintCode 125 · Backpack II.java

Backpack with Value array:
function:
dp[i][j] = Math.max(dp[i - 1][j - A[i - 1]] + V[i - 1], dp[i - 1][j]); (when you take that ith item)
or
dp[i][j] += dp[i - 1][j]; (when you don't take that ith item)
public class Solution {
/**
* @param m: An integer m denotes the size of a backpack
* @param A: Given n items with size A[i]
* @param V: Given n items with value V[i]
* @return: The maximum value
*/
public int backPackII(int m, int[] A, int[] V) {
// write your code here
if (A == null || A.length == 0) {
return 0;
}
int n = A.length;
// init
int[][] dp = new int[n+1][m+1];
dp[0][0] = 0;
for (int j = 1; j <= m; j++) {
dp[0][j] = 0;
}
// dp: functions
int maximumJ = Integer.MIN_VALUE;
for (int i = 1; i <= n; i++) {
dp[i][0] = 0;
for (int j = 1; j <= m; j++) {
if (j - A[i-1] >= 0) {
dp[i][j] = Math.max(dp[i - 1][j - A[i - 1]] + V[i - 1], dp[i - 1][j]);
} else {
dp[i][j] += dp[i - 1][j];
}
}
}
// dp: answer
return dp[n][m];
}
}

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