文章作者：Tyan
博客：noahsnail.com | CSDN | 简书
1. Description
Search a 2D Matrix
2. Solution
- Treated as a matrix
class Solution {
public:
bool searchMatrix(vector<vector<int>>& matrix, int target) {
int rows = matrix.size();
if(rows == 0) {
return false;
}
int columns = matrix[0].size();
if(columns == 0) {
return false;
}
if(target < matrix[0][0]) {
return false;
}
if(target > matrix[rows -1][columns - 1]) {
return false;
}
int top = 0;
int bottom = rows - 1;
int center = 0;
while(top <= bottom) {
center = (top + bottom) / 2;
if(target == matrix[center][0]) {
return true;
}
else if(target < matrix[center][0]) {
bottom = center - 1;
}
else {
top = center + 1;
}
}
if(target < matrix[center][0]) {
center--;
}
int left = 0;
int right = columns - 1;
int middle = 0;
while(left <= right) {
middle = (left + right) / 2;
if(target == matrix[center][middle]) {
return true;
}
else if(target < matrix[center][middle]) {
right = middle - 1;
}
else {
left = middle + 1;
}
}
return false;
}
};
- Treated as an array
class Solution {
public:
bool searchMatrix(vector<vector<int>>& matrix, int target) {
int rows = matrix.size();
if(rows == 0) {
return false;
}
int columns = matrix[0].size();
if(columns == 0) {
return false;
}
if(target < matrix[0][0]) {
return false;
}
if(target > matrix[rows -1][columns - 1]) {
return false;
}
int left = 0;
int right = rows * columns - 1;
int middle = 0;
while(left <= right) {
middle = (left + right) >> 1;
int current = matrix[middle / columns][middle % columns];
if(target == current) {
return true;
}
else if(target < current) {
right = middle - 1;
}
else {
left = middle + 1;
}
}
return false;
}
};
