Project Euler - Problem 11

最新推荐文章于 2019-04-30 16:17:05 发布

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本文介绍了一个C++程序，该程序从一个20x20的矩阵文件中读取整数，并找出任意四个相邻数字（水平、垂直或对角方向）的最大乘积。

#include<iostream> #include<fstream> #include<sstream> #include<math.h> #include<time.h> #include<string> using namespace std; int main() { double start = clock(),end(0); ifstream infile; infile.open("11.txt"); if(!infile) { cerr<<"can't open the file."<<endl; exit(1); } //将文件内容写入二维数组中 int a[20][20]; for (int l = 0; l<20; l++) { for (int r = 0; r<20 ; r++) { infile >> a[l][r]; } } int maxproduct = 0; for (int l = 0; l<20; l++) { for (int r = 0; r<20 ; r++) { if(0 == a[l][r]) //排除为0的元素 continue; int temp = 0; //横向 if(r<=16) { temp = a[l][r] * a[l][r+1] * a[l][r+2] * a[l][r+3]; if(temp > maxproduct) maxproduct = temp; } //纵向 if(l<=16) { temp = a[l][r] * a[l+1][r] * a[l+2][r] * a[l+3][r]; if(temp > maxproduct) maxproduct = temp; } //斜/向 if(r<=16 && l<=16) { temp = a[l][r] * a[l+1][r+1] * a[l+2][r+2] * a[l+3][r+3]; if(temp > maxproduct) maxproduct = temp; } //斜/向 if(r>=4 && l<=16) { temp = a[l][r] * a[l+1][r-1] * a[l+2][r-2] * a[l+3][r-3]; if(temp > maxproduct) maxproduct = temp; } } } cout << "the greatest product is "<< maxproduct << endl; end = clock(); double runtime = (end - start)/1000; cout << "run time is " << runtime << endl; system("PAUSE"); return 0; }