CareerCup

//input a 4X13 matrix with 4 suits and 13 ranks of cards. set cards[suit][rank] to 1 if this card in hand.
    public static boolean handClear(int[][] cards, int hand) {

        if(hand == 0) return true;

        for(int rank = 12; rank >= 0; rank--) {

            for(int suit = 0; suit < 4; suit++) {

                if(cards[suit][rank] == 1) { //if cards[suit][rank] in hand

                    cards[suit][rank] = 0; hand--;

                    int smallerRank = rank == 0 ? 12: rank - 1; // look for straight flush that end with this card
                                                                // watch for Ace as a special case that ***QKA and A23*** both valid
                    if(cards[suit][smallerRank] == 1) {

                        cards[suit][smallerRank] = 0; hand--;

                        int r = smallerRank - 1;

                        for(; r >= 0 && cards[suit][r] == 1; r--) {   //try playing the straight flush found

                            cards[suit][r] = 0; hand--;

                            if(handClear(cards, hand)) return true;

                        }

                        r++;

                        for(; r <= smallerRank; r++) {  //backtrack if play did not work

                            cards[suit][r] = 1; hand++;

                        }

                    }
                    //look for 3/4 of a kind for cards[suit][rand]
                    int n = cards[0][rank] + cards[1][rank] + cards[2][rank] + cards[3][rank];

                    if(n == 3 || n == 2) {

                        int tmp1 = cards[(suit + 1) % 4][rank],
                            tmp2 = cards[(suit + 2) % 4][rank],
                            tmp3 = cards[(suit + 3) % 4][rank];

                        cards[(suit + 1) % 4][rank] = 0; //try playing the 3/4 of a kind
                        cards[(suit + 2) % 4][rank] = 0;
                        cards[(suit + 3) % 4][rank] = 0;
                        hand -= n;

                        if(handClear(cards, hand)) return true;

                        cards[(suit + 1) % 4][rank] = tmp1;   //backtrack if play did not work
                        cards[(suit + 2) % 4][rank] = tmp2;
                        cards[(suit + 3) % 4][rank] = tmp3;
                        hand += n;

                    }

                    cards[suit][rank] = 1; hand++;
                }
            }
        }
        return false;

    }

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In first example why it returned false when it had 3 qs or even a flush of 3 AKQ

#include<iostream>
using namespace std;
int main() {
	bool pack[4][13] = {{0,0}};
	bool play=false;
	int pack_type=0,number = 0,cnt=0;
	
	cout<<"\nEnter pack_type (1-spade, 2-diamond, 3-heart, 4-club (0 for break):"; cin>>pack_type;
	cout<<"Enter number (Ace-1, 2-2,3-3..., J-11, Q-12, K-13 (0 for break):"; cin>> number;
	
	while (pack_type !=0 && number !=0) {
		if(pack_type <1 || pack_type>4 || number<1 ||number >13) 
			return -1;
		if (pack[pack_type-1][number-1]==true) {
			cout<<"Dup entry"; 
			return -1;
		}
		pack[pack_type-1][number-1]=true;
		cnt++;
		cout<<"\nEnter pack_type (1-spade, 2-diamond, 3-heart, 4-club (0 for break):"; cin>>pack_type;
		cout<<"Enter number (Ace-1, 2-2,3-3..., J-11, Q-12, K-13 (0 for break):"; cin>> number;
	}
	
	if(cnt<3) cout<<"Can't play!!";
	
	for(int i=0;i<4;i++) {
		for (int j=0;j<11;j++) {
			if (pack[i][j] && pack[i][j+1] && pack[i][j+2]) {
				cout<<"Trace1: I can continue to play!!";
				printf("Combo :\n %d->%d \n %d->%d \n%d->%d \n",i+1,j+1,i+1,j+2,i+1,j+3);
				play=true;
				break;
			}
		}
		if(play) {
			return 0;
		}
	}
	
	for(int i=0;i<2;i++) {
		for (int j=0;j<13;j++) {
			if(pack[i][j] &&pack[i+1][j] &&pack[i+2][j]) {
					cout<<"Trace 2:I can continue to play!!";
					printf("Combo :\n %d->%d \n %d->%d \n%d->%d \n",i+1,j+1,i+2,j+1,i+3,j+1);
					play=true;
					break;
			}
		}
		if(play) {
			return 0;
		}
	}
	for(int i=0;i<4;i++) {
		for (int j=0;j<11;j++) {
			cout<<pack[i][j];
		} 
		cout<<'\n';
	}
	cout<<"I cannot continue to play!!";
	return -1;
}