Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties:
- Integers in each row are sorted from left to right.
- The first integer of each row is greater than the last integer of the previous row.
For example,
Consider the following matrix:
[
[1, 3, 5, 7],
[10, 11, 16, 20],
[23, 30, 34, 50]
]
Given target = 3, return true.
题意：三个条件，
- 数字应该从左到右的增加
- 每行的第一个也应该是个递增的
- 给一个target看这里面是否包含
都满足就可以了。
class Solution {
public boolean searchMatrix(int[][] matrix, int target) {
boolean isHaveTarget = false;
for (int i = 0; i < matrix.length - 1; i++) {
for (int j = 0; j < matrix[0].length; j++) {
if (matrix[i][j] >= matrix[i + 1][j]) {
return false;
}
}
}
for (int i = 0; i < matrix.length - 1; i++) {
if (matrix[i][0] > matrix[i + 1][0]) {
return false;
}
}
for (int i = 0; i < matrix.length; i++) {
for (int j = 0; j < matrix[0].length; j++) {
if (matrix[i][j] == target) {
isHaveTarget = true;
}
}
return isHaveTarget;
}
}
