LeetCode120 Triangle

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详细见：leetcode.com/problems/triangle

Java Solution: github

package leetcode;/* * Given a triangle, find the minimum path sum from top to bottom.  * Each step you may move to adjacent numbers on the row below.For example, given the following triangle[     [2],    [3,4],   [6,5,7],  [4,1,8,3]]The minimum path sum from top to bottom is 11 (i.e., 2 + 3 + 5 + 1 = 11).Note:Bonus point if you are able to do this using only O(n) extra space, where n is the total number of rows in the triangle. */import java.util.List;public class P120_Triangle {public static void main(String[] args) {List<List<Integer>> list = tools.Utils.C_生成List_List_Integer__从二维数组(new int[][] {{1},{-1, 1},//{0, 2, 3},//{0, 4, 5, 6},//{1, 0, 3, 6, 9}});Solution2 s = new Solution2();System.out.println(s.minimumTotal(list));}/* * TLE */static class Solution {int min = Integer.MAX_VALUE;int I = 0;    public int minimumTotal(List<List<Integer>> triangle) {    I = triangle.size() - 1;    if (I < 0) {    return 0;    } else if (I == 0) {    return triangle.get(0).get(0);    }        return search(triangle, 0, 0);    }private int search(List<List<Integer>> triangle, int i, int j) {if (j < 0 || j > i) {return Integer.MAX_VALUE;}if (i == I) {return triangle.get(i).get(j);}return Math.min(search(triangle, i + 1, j), search(triangle, i + 1, j + 1)) + triangle.get(i).get(j);}}/* * 艰难AC * 3 ms */static class Solution2 {    public int minimumTotal(List<List<Integer>> triangle) {    int len = 0;    if (triangle == null || (len = triangle.size()) <= 0) {    return 0;    } else if (len == 1) {    return triangle.get(0).get(0);    }    int[] arr = new int[len + 1];    for (int list_count = len - 1; list_count > -1; list_count --) {    List<Integer> list_now = triangle.get(list_count);    arr[0] = list_now.get(0) + Math.min(arr[0], arr[1]);    for (int i = 1; i <= list_count; i ++) {    arr[i] = list_now.get(i) + Math.min(arr[i], arr[i + 1]);    }    }    return arr[0];    }}}

C Solution: github

/*    url: leetcode.com/problems/triangle    AC 6ms 4.76%*/#include <stdio.h>#include <stdlib.h>#include <limits.h>long _min(long* m, int i, int j, int k) {    if (i == -1) return m[j];    if (j >= k) return m[i];    return m[i] < m[j] ? m[i] : m[j];}int minimumTotal(int** t, int rn, int *cn) {    int i = 0, j = 0;    long ans = LONG_MAX;    long* m = NULL;    if (rn < 1) return 0;    m = (long*) malloc(sizeof(long) * cn[rn-1]);    for (j = 0; j < cn[rn-1]; j ++) m[j] = 0l;    m[0] = t[0][0];    for (i = 1; i < rn; i ++) {        for (j = cn[i]-1; j > -1; j --)            m[j] = t[i][j] + _min(m, j-1, j, cn[i-1]);    }    for (j = 0; j < cn[rn-1]; j ++)        ans = ans > m[j] ? m[j] : ans;    free(m);    return ans;}

Python Solution: github

#coding=utf-8'''    url: leetcode.com/problems/triangle    @author:     zxwtry    @email:      zxwtry@qq.com    @date:       2017年5月4日    @details:    Solution:  68ms 26.43%'''class Solution(object):    def minimumTotal(self, t):        """        :type t: List[List[int]]        :rtype: int        """        tn = 0 if t == None else len(t)        if tn == 0: return 0        m = [0]*tn        m[0] = t[0][0]        for i in range(1, tn):            for j in range(i, -1, -1):                m[j] = t[i][j] + min(m[j-1] if j == i else m[j], m[j] if j==0 else m[j-1])        return min(m)    if __name__ == "__main__":    t = [[-1],[2,3],[1,-1,-3]]    print(Solution().minimumTotal(t))

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