2021-08-11 function pointer

Young's matrix

There is a matrix of numbers , Each row of the matrix is incremented from left to right , The matrix is increasing from top to bottom , Please write a program to find out whether a number exists in such a matrix .

requirement ： Time complexity is less than O(N);

#include<stdio.h>
void find_k(int a[3][3], int k, int x, int y)
{
	// According to the characteristics of matrix increment , Starting from the upper right corner, the time complexity will be relatively small ;
	int n= 0;
	int m = y - 1;
	// Abscissa cannot be greater than 3, The ordinate should be greater than or equal to 0;
	while (n < x && m >= 0) {
		// If smaller , Abscissa plus 
		if (a[n][m] < k) {
			n++;
		}
		// If it's bigger , Minus ordinate 
		else if (a[n][m] > k) {
			m--;
		}
		else {
			printf(" Found the subscript is :%d %d", n, m);
			return;
		}
	}
	printf(" Can't find \n");
}
int main()
{
	int k = 17;
	int a[3][3] = { 1,2,3,4,5,6,7,8,9 };
	find_k(a,k,3,3);
	return 0;
}