48 lines
1.5 KiB
Java
48 lines
1.5 KiB
Java
// Source : https://oj.leetcode.com/problems/minimum-path-sum/
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// Inspired by : http://www.jiuzhang.com/solutions/minimum-path-sum/
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// Author : Lei Cao
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// Date : 2015-10-12
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/**********************************************************************************
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*
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* Given a m x n grid filled with non-negative numbers, find a path from top left to
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* bottom right which minimizes the sum of all numbers along its path.
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*
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* Note: You can only move either down or right at any point in time.
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*
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**********************************************************************************/
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package dynamicProgramming.minimumPathSum;
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public class minimumPathSum {
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/**
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* @param grid: a list of lists of integers.
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* @return: An integer, minimizes the sum of all numbers along its path
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*/
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public int minPathSum(int[][] grid) {
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if (grid.length == 0 || grid[0].length == 0) {
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return 0;
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}
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int m = grid.length;
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int n = grid[0].length;
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int[][] matrix = new int[m][n];
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matrix[0][0] = grid[0][0];
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for (int i = 1; i < m; i++) {
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matrix[i][0] = grid[i][0] + matrix[i-1][0];
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}
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for (int i = 1; i < n; i++) {
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matrix[0][i] = grid[0][i] + matrix[0][i-1];
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}
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for (int i = 1; i < m; i++) {
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for (int j = 1; j < n; j++) {
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matrix[i][j] = grid[i][j] + Math.min(matrix[i-1][j], matrix[i][j-1]);
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}
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}
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return matrix[m-1][n-1];
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}
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}
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