标签:border tracking nim rac uri asc line link sans
题目:
Given numRows, generate the first numRows of Pascal‘s triangle.
For example, given numRows = 5,
Return
[ [1], [1,1], [1,2,1], [1,3,3,1], [1,4,6,4,1] ]
分析:打印杨辉三角。
numRows=0 或者 numRows=1时特殊处理。numRows>=2时都是有规律的了。
代码例如以下:
#include <iostream>
#include <vector>
using namespace std;
vector<vector<int> > generate(int numRows)
{
vector<vector<int> > res;
vector<int> currentRow;
vector<int> lastRow;
if(numRows <= 0)
return res;
currentRow.push_back(1);
res.push_back(currentRow);
if (numRows == 1)
return res;
for (int i=0; i<numRows-1; i++)
{
lastRow = currentRow;
currentRow.clear();
currentRow.push_back(1);
for(int j=0; j<lastRow.size()-1; j++)
currentRow.push_back(lastRow[j] + lastRow[j+1]);
currentRow.push_back(1);
res.push_back(currentRow);
}
return res;
}
int _tmain(int argc, _TCHAR* argv[])
{
vector<vector<int> > res = generate(5);
// 打印结果
for (int i=0; i<res.size(); i++)
{
vector<int> row = res[i];
for (int j=0; j<row.size(); j++)
cout << row[j] <<" ";
cout << endl;
}
return 0;
}
标签:border tracking nim rac uri asc line link sans
原文地址:https://www.cnblogs.com/ldxsuanfa/p/9934795.html