Detect consecutive objects with a common attribute in 2-D array - c++

Question

I have a 2-D array of gems, all the gems have been given random color. Now i want to detect if three or more consecutive gems in a row or column has the same color. If so i want to do some action with those gems.
Gem gems[10][10];
for(int i=0;i<10;++i){
for(int j=0;j<10;++j){
gems[i][j].setColor(GetRandInRange(0,6));
}
}
bool detectMatch(){
for(int i=0;i<10;++i){
for(int j=0;j<10;++j){
// Code to detect three or more consecutive gems with same color
// Give some special color to the matched gems
}
}
Here is how i tried but it doesn't work
bool GameBoard::findMatch(){
for(int i=0;i<10;++i){
int count=0;
for(int j=0;j<10;++j){
if(j!=0){
if(gems[i][j].getColor()==gems[i][j-1].getColor()){ //Color same with previous one
int a=i, b=j;
while(gems[a][b].getColor()==gems[i][j].getColor() && (a<10 && b<10)){ // Check till the color does not match
count++;
a++;
b++;
}
if(count>=3){ //If 3 or more have matched
for(int a=i, b=j, c=0;c<count;++c){
gems[a][b].setColor(0);
}
return true;
}
}
}
}
}
return false;
}
if you can help me with this code please

Answer 1

Here's how I'd go about it. You need to do two scans. First, you need to scan for runs in one direction, then the other. It's much simpler than trying to loop through once.
I first check for horizontal runs, exiting as soon as one longer than 2 is found. Same with the vertical ones. Your function has a bool signature, so I've assumed you'll use another function to determine the location of the run - you could easily return a struct that held the position, direction and length from the findMatch method.
"use strict";
window.addEventListener('load', onLoaded, false);
var gems;
function onLoaded(evt) {
// create and initialize the array
gems = new Array();
for (var row = 0; row < 10; row++) {
let curRow = new Array();
for (var col = 0; col < 10; col++) {
let curCell = new Gem();
curCell.setColor(GetRandInRange(0, 6));
curRow.push(curCell);
}
gems.push(curRow);
}
// display it for the user
displayGems();
// check if there's 3 or more in a vertical or horizontal line.
console.log(hasMatch());
}
class Gem {
setColor(colIndex) {
this.color = colIndex;
}
getColor() {
return this.color;
}
};
function displayGems() {
var str = '';
for (var row = 0; row < 10; row++) {
if (row != 0)
str += "\n";
var dat = gems[row];
dat.forEach((gem, idx) => {
if (idx != 0)
str += ', ';
str += gem.getColor();
});
}
console.log(str);
}
function GetRandInRange(lower, upper) {
return ((Math.random() * (upper - lower)) + lower + 0.5) >> 0;
}
function hasMatch() {
let matchFound = 0;
// scan #1 - horizontally on each row
for (var row = 0; row < 10; row++) {
let last = undefined;
let runLength = 0;
for (var col = 0; col < 10; col++) {
let cur = gems[row][col].getColor();
if (cur == last) {
runLength++
if (runLength > 2) {
console.log(`horiz - ${row+1}`);
return true;
}
} else {
runLength = 0;
last = cur;
}
}
}
for (var col = 0; col < 10; col++) {
let last = undefined;
let runLength = 1;
for (var row = 0; row < 10; row++) {
let cur = gems[row][col].getColor();
if (cur == last) {
runLength++;
if (runLength > 2) {
console.log(`vert - ${col+1}`);
return true;
}
} else {
runLength = 1;
last = cur;
}
}
}
return false;
}