20x20 Int Grid..Maximum product of 4 num's

jwroblewski (39)
Euler project help again!
Problem 11

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//euler prob_11
#include <iostream>
using namespace std;
int Horiz_Max(int*);
int Vert_Max(int*);
int Diag_Max(int*);
int main(){
	int *ListPtr,max=0,x;
        int List[401]=            {8,2,22,97,38,15,0,40,0,75,4,5,7,78,52,12,50,77,91,8,      //   1
				  49,49,99,40,17,81,18,57,60,87,17,40,98,43,69,48,4,56,62,0, //   2
				  81,49,31,73,55,79,14,29,93,71,40,67,53,88,30,3,49,13,36,65,//   3
				  52,70,95,23,4,60,11,42,69,24,68,56,1,32,56,71,37,2,36,91,  //   4
				  22,31,16,71,51,67,63,89,41,92,36,54,22,40,40,28,66,33,13,80,//  5
				  24,47,32,60,99,3,45,2,44,75,33,53,78,36,84,20,35,17,12,50,  //  6
				  32,98,81,28,64,23,67,10,26,38,40,67,59,54,70,66,18,38,64,70,//  7
				  67,26,20,68,2,62,12,20,95,63,94,39,63,8,40,91,66,49,94,21, //   8
				  24,55,58,5,66,73,99,26,97,17,78,78,96,83,14,88,34,89,63,72, //  9
				  21,36,23,9,75,0,76,44,20,45,35,14,0,61,33,97,34,31,33,95,   //  10
				  78,17,53,28,22,75,31,67,15,94,3,80,4,62,16,14,9,53,56,92,   //  11
				  16,39,5,42,96,35,31,47,55,58,88,24,0,17,54,24,36,29,85,57,  //  12
				  86,56,0,48,35,71,89,7,5,44,44,37,44,60,21,58,51,54,17,58,   //  13
				  19,80,81,68,5,94,47,69,28,73,92,13,86,52,17,77,4,89,55,40,  //  14
				  4,52,8,83,97,35,99,16,7,97,57,32,16,26,26,79,33,27,98,66,    // 15  
				  88,36,68,87,57,62,20,72,3,46,33,67,46,55,12,32,63,93,53,69, //  16
				  4,42,16,73,38,25,39,11,24,94,72,18,8,46,29,32,40,62,76,36,  //  17
				  20,69,36,41,72,30,23,88,34,62,99,69,82,67,59,85,74,4,36,16, //  18
				  20,73,35,29,78,31,90,1,74,31,49,71,48,86,81,16,23,57,5,54,  //  19
				  1,70,54,71,83,51,54,69,16,92,33,48,61,43,52,1,89,19,67,48}; //  20
	ListPtr=List;
	
	x=Horiz_Max(ListPtr);if(x>max)max=x;
	x=Vert_Max(ListPtr);if(x>max)max=x;
	x=Diag_Max(ListPtr);if(x>max)max=x;
	
	cout << max << endl;
	
	return 0;
}
int Horiz_Max(int*ListPtr){
	int sum=1,max=0,j;
	for(j=0;j<=380;j+=20){
		for(int i=j;i<17+j;i++){
			for(int k=i;k<i+4;k++)
				sum*=ListPtr[k];
			if(sum>max)max=sum;
		}
		sum=1;
	}
	return max;
}
int Vert_Max(int*ListPtr){
	int sum=1,max=0;
	
	for(int k=0;k<=19;k++){
		for(int i=k;i<340+k;i+=20){
			for(int j=i;j<=60+i;j+=20)
				sum*=ListPtr[j];
			if(sum>max)max=sum;
		}		
		sum=1;
	}
	return max;
}
int Diag_Max(int*ListPtr){
	int sum=1,max=0;
	
	for(int k=0;k<=320;k+=20){          //fowards facing diaganol
		for(int j=k;j<=16+k;j++){
			for(int i=j;i<=63+j;i+=21){
				sum*=ListPtr[i];
			}
			if(sum>max)max=sum;sum=1;
		}
	}
	sum=1;
	for(int i=3;i<=339;i+=20){            //backwards facing diaganol
		for(int k=i;k<=16+i;k++){
			for(int j=k;j<=57+k;j+=19){
				sum*=ListPtr[j];
			}
			if(sum>max)max=sum;sum=1;
		}
	}
	return max;
}

i checked each function and can't figure out whats wrong. Is there something i'm missing?

link to the problem: http://projecteuler.net/problem=11
Last edited on
BrokenSilenceDev (99)
What was the error? I don't really understand if the title is what the error is.
jwroblewski (39)
sorry. i dont get the right answer when i run it.
jwroblewski (39)
UPDATE: the problem was that my reset of sum wasnt happening, due to its improper placement. Moved it and poof, the right answer.

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//euler prob_11
#include <iostream>
using namespace std;
int Horiz_Max(int*);
int Vert_Max(int*);
int Diag_Max(int*);
int main(){
	int *ListPtr,max=0,x;
	int List[401]={8,2,22,97,38,15,0,40,0,75,4,5,7,78,52,12,50,77,91,8,      //   1
				  49,49,99,40,17,81,18,57,60,87,17,40,98,43,69,48,4,56,62,0, //   2
				  81,49,31,73,55,79,14,29,93,71,40,67,53,88,30,3,49,13,36,65,//   3
				  52,70,95,23,4,60,11,42,69,24,68,56,1,32,56,71,37,2,36,91,  //   4
				  22,31,16,71,51,67,63,89,41,92,36,54,22,40,40,28,66,33,13,80,//  5
				  24,47,32,60,99,3,45,2,44,75,33,53,78,36,84,20,35,17,12,50,  //  6
				  32,98,81,28,64,23,67,10,26,38,40,67,59,54,70,66,18,38,64,70,//  7
				  67,26,20,68,2,62,12,20,95,63,94,39,63,8,40,91,66,49,94,21, //   8
				  24,55,58,5,66,73,99,26,97,17,78,78,96,83,14,88,34,89,63,72, //  9
				  21,36,23,9,75,0,76,44,20,45,35,14,0,61,33,97,34,31,33,95,   //  10
				  78,17,53,28,22,75,31,67,15,94,3,80,4,62,16,14,9,53,56,92,   //  11
				  16,39,5,42,96,35,31,47,55,58,88,24,0,17,54,24,36,29,85,57,  //  12
				  86,56,0,48,35,71,89,7,5,44,44,37,44,60,21,58,51,54,17,58,   //  13
				  19,80,81,68,5,94,47,69,28,73,92,13,86,52,17,77,4,89,55,40,  //  14
				  4,52,8,83,97,35,99,16,7,97,57,32,16,26,26,79,33,27,98,66,    // 15  
				  88,36,68,87,57,62,20,72,3,46,33,67,46,55,12,32,63,93,53,69, //  16
				  4,42,16,73,38,25,39,11,24,94,72,18,8,46,29,32,40,62,76,36,  //  17
				  20,69,36,41,72,30,23,88,34,62,99,69,82,67,59,85,74,4,36,16, //  18
				  20,73,35,29,78,31,90,1,74,31,49,71,48,86,81,16,23,57,5,54,  //  19
				  1,70,54,71,83,51,54,69,16,92,33,48,61,43,52,1,89,19,67,48}; //  20
	ListPtr=List;
	
	x=Horiz_Max(ListPtr);if(x>max)max=x;
	x=Vert_Max(ListPtr);if(x>max)max=x;
	x=Diag_Max(ListPtr);if(x>max)max=x;
	
	cout << max << endl;
	
	return 0;
}
int Horiz_Max(int*ListPtr){
	int sum=1,max=0,j;
	for(j=0;j<=380;j+=20){
		for(int i=j;i<17+j;i++){
			for(int k=i;k<i+4;k++)
				sum*=ListPtr[k];
			if(sum>max)max=sum; sum=1;    //<--- changed sum=1 location
		}
		
	}
	return max;
}
int Vert_Max(int*ListPtr){
	int sum=1,max=0;
	
	for(int k=0;k<=19;k++){
		for(int i=k;i<340+k;i+=20){
			for(int j=i;j<=60+i;j+=20)
				sum*=ListPtr[j];
			if(sum>max)max=sum;sum=1;  //<--- changed sum=1 location
		}		
		
	}
	return max;
}
int Diag_Max(int*ListPtr){
	int sum=1,max=0;
	
	for(int k=0;k<=320;k+=20){          //fowards facing diaganol
		for(int j=k;j<=16+k;j++){
			for(int i=j;i<=63+j;i+=21){
				sum*=ListPtr[i];
			}
			if(sum>max)max=sum;sum=1;
		}
	}
	sum=1;
	for(int i=3;i<=339;i+=20){            //backwards facing diaganol
		for(int k=i;k<=16+i;k++){
			for(int j=k;j<=57+k;j+=19){
				sum*=ListPtr[j];
			}
			if(sum>max)max=sum;sum=1;
		}
	}
	return max;
}
Last edited on
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