POJ 3318-matrix multiplication (compression matrix with O (n^2) method to find matrix equality)

Title Address: POJ 3318
Test instructions: There are 3 n*n matrix a,b,c, q AB is equal to C.
Idea: The topic description is very simple, is to use matrix multiplication, but it is obvious that the time complexity of matrix multiplication is O (n^3), obviously timed out. How does that improve? is to use the compression matrix method:
Set matrix R is a matrix of 1*n, according to the nature of the matrix, if a*b*r=c*r, then a*b=c. As can be seen, although more than a matrix, but the time complexity of the O (n^2). So the question is how the determinant of this r is set, the random algorithm used by someone, but the random algorithm may have errors on the key points, you can set R as an ascending sequence {... ｝。

#include <stdio.h>#include <math.h>#include <string.h>#include <stdlib.h>#include <iostream>#include <sstream>#include <algorithm>#include <set>#include <queue>#include <stack>#include <map>//#pragma comment (linker, "/stack:102400000,102400000")using namespace STD;typedef Long LongLL;Const intinf=0x3f3f3f3f;Const DoublePi=ACOs(-1.0);Const Doubleesp=1e-6;intmaxn=510; LL a[510][510]; LL b[510][510]; LL ra[510]; LL c[510][510]; LL rab[510]; LL rc[510];intCheckintN) {intI,j; for(i=0; i<n;i++) for(j=0; j<n;j++) ra[i]+=a[j][i]* (j+1); for(i=0; i<n;i++) for(j=0; j<n;j++) Rab[i]+=ra[j]*b[j][i]; for(i=0; i<n;i++) for(j=0; j<n;j++) rc[i]+=c[j][i]* (j+1);/*for (i=0;i<n;i++) printf ("%lld", Rab[i]);        printf ("\ n");        for (i=0;i<n;i++) printf ("%lld", Rc[i]);        printf ("\ n"); */     for(i=0; i<n;i++) {if(Rab[i]!=rc[i])return 0; }return 1;}intMain () {intN while(~scanf("%d", &n)) {memset(RA,0,sizeof(RA));memset(Rab,0,sizeof(RAB));memset(RC,0,sizeof(RC)); for(intI=0; i<n;i++) for(intj=0; j<n;j++)scanf("%lld", &a[i][j]); for(intI=0; i<n;i++) for(intj=0; j<n;j++)scanf("%lld", &b[i][j]); for(intI=0; i<n;i++) for(intj=0; j<n;j++)scanf("%lld", &c[i][j]);if(check (n))puts("YES");Else            puts("NO"); }return 0;}

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POJ 3318-matrix multiplication (compression matrix with O (n^2) method to find matrix equality)