my C99 solution to advent of code 2017 day 3 part 2

aoc3.c

#include <stdint.h>
#include <stdio.h>
#include <string.h>

// returns the sum of all 8 adjacent cells to element [cy][cx] in a 2D array, with bounds checking
uint32_t setdata(uint32_t root_max, uint32_t data[][root_max], uint32_t cx, uint32_t cy){
	uint32_t counter = 0;
	if(cx + 1 < root_max){
		counter += data[cy][cx+1];
		if(cy - 1 >= 0)
			counter += data[cy-1][cx+1];
		if(cy + 1 < root_max)
			counter += data[cy+1][cx+1];
	}
	
	if(cx - 1 >= 0){
		counter += data[cy][cx-1];
		if(cy - 1 >= 0)
			counter += data[cy-1][cx-1];
		if(cy + 1 < root_max)
			counter += data[cy+1][cx-1];
	}
	
	if(cy - 1 >= 0)
		counter += data[cy-1][cx];
	if(cy + 1 < root_max)
		counter += data[cy+1][cx];
		
	return counter;
}

uint32_t solve(uint32_t input){
	
	// calculate the side length (root_max) of the square ring 'input' lies on
	uint32_t root_max = 0, square = 0;
	while(square < input){
		root_max += 1;
		square = root_max * root_max;
	}
	
	uint32_t data[root_max][root_max];
	memset(&data[0][0], '\0', sizeof(data));
	
	uint32_t cx = root_max/2, cy = root_max/2;
	
	data[cy][cx] = 1;
	uint32_t root = 3;
	uint32_t dim = root - 1;
	cx += 1; // start on the cell 1-unit left of center
	
	// GENERATE THE SPIRAL!!!
	// up dim-1, right dim, down dim, left dim+1, root += 2, recalculate dim, repeat
	while(root < root_max){
		// traverse up dim-1
		for(int i=0; i<dim-1; i+=1){
			// set value at cx,cy
			data[cy][cx] = setdata(root_max, data, cx, cy);
			if(data[cy][cx] > input) goto WE_FOUND_IT;
			cy -= 1;
		}
		
		// traverse right dim
		for(int i=0; i<dim; i+=1){
			data[cy][cx] = setdata(root_max, data, cx, cy);
			if(data[cy][cx] > input) goto WE_FOUND_IT;
			cx -= 1;
		}
		
		// traverse down dim
		for(int i=0; i<dim; i+=1){
			data[cy][cx] = setdata(root_max, data, cx, cy);
			if(data[cy][cx] > input) goto WE_FOUND_IT;
			cy += 1;
		}
		
		// traverse left dim+1
		for(int i=0; i<dim+1; i+=1){
			data[cy][cx] = setdata(root_max, data, cx, cy);
			if(data[cy][cx] > input) goto WE_FOUND_IT;
			cx += 1;
		}
		
		root += 2;
		dim = root -1;
	}
	
	return -1;
	
	WE_FOUND_IT:
	return data[cy][cx];
}

int main(int argc, char **argv){
	uint32_t challenge_input = 265149;
	printf("%i\n", solve(challenge_input));
	return 0;	
}