【Hot100】LeetCode—240. 搜索二维矩阵 II

目录

• [1- 思路](#1- 思路)
• • 二分法
• [2- 实现](#2- 实现)
• • [⭐240. 搜索二维矩阵 II------题解思路](#⭐240. 搜索二维矩阵 II——题解思路)
• [3- ACM 实现](#3- ACM 实现)

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• 原题连接：240. 搜索二维矩阵 II

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1- 思路

二分法

• 针对每行一维数组进行二分，对 target 进行二分

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2- 实现

⭐240. 搜索二维矩阵 II------题解思路

class Solution {
    public boolean searchMatrix(int[][] matrix, int target) {
        for(int [] m:matrix){
            if(binarySearch(m,target)>=0){
                return true;
            }
        }
        return false;
    }

    private int binarySearch(int[] nums,int target){
        int left = 0;
        int right = nums.length-1;

        while(left<=right){
            int mid = (right+left)/2 ;
            if(nums[mid]==target){
                return mid;
            }else if(nums[mid] < target){
                left = mid+1;
            }else{
                right = mid-1;
            }
        }
        return -1;
    }
}

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3- ACM 实现

public class searchMatrix {
    
    private static boolean searchM(int[][] matrix,int target){
        for (int[] n:matrix){
            if(binarySearch(n,target)>=0){
                return true;
            }
        }
        return false;
    }

    private static int binarySearch(int[] nums,int target){
        int left = 0;
        int right = nums.length;
        while(left<=right){
            int mid = (left+right)/2;
            if(nums[mid] == target){
                return mid;
            }else if (nums[mid] > target){
                right = mid-1;
            }else{
                left = mid+1;
            }
        }
        return -1;
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("输入数组行数m");
        int m = sc.nextInt();
        System.out.println("输入数组列数n");
        int n = sc.nextInt();
        int[][] nums = new int[m][n];
        for(int i = 0 ;i < m;i++){
            for(int j = 0 ; j < n;j++){
                nums[i][j] = sc.nextInt();
            }
        }
        System.out.println("输入target");
        int target = sc.nextInt();
        System.out.println("结果是"+searchM(nums,target));
    }
}