【LC】剑指 Offer 04. 二维数组中的查找

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题目描述

题解一：暴力for

class Solution {
public:
    bool findNumberIn2DArray(vector<vector<int>>& matrix, int target) {
        int ln = matrix.size();
        if(ln == 0 ) return false;
        int lm = matrix.front().size();
       
        for(int i = 0; i < ln; ++i)
        {
            for(int j = 0; j < lm; ++j)
            {
                if(matrix[i][j] == target)
                {
                    return true;
                }
            }
        }
        return false;
    }
};

题解二：缩小范围

class Solution {
public:
    bool findNumberIn2DArray(vector<vector<int>>& matrix, int target) {
        int ln = matrix.size();
        if(ln == 0) return false;
        int lm = matrix.front().size();
        bool res = false;

        int row = 0;
        int col = lm - 1;
        while(row < ln && col >= 0)
        {
            if(matrix[row][col] == target)
            {
                res = true;
                break;
            }
            else if(matrix[row][col] > target)
            {
                --col;
            }
            else
            {
                ++row;
            }
        }
        return res;
    }
};