LeetCode OJ——Pascal's Triangle

http://oj.leetcode.com/problems/pascals-triangle/ 杨辉三角

先分析数据，找出规律

ans[row][col] = ans[row-1][col-1]+ans[row-1][col]

#include <iostream>
#include <vector>
#include <string>
using namespace std;

class Solution {
public:
    vector<vector<int> > generate(int numRows) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
        vector<vector<int> > ans;
        ans.clear();
        if(numRows<=)
            return ans;
        //
        vector<int> onepiece;
        onepiece.push_back();
        ans.push_back(onepiece);
        if(numRows == )
            return ans;
        //
        onepiece.clear();
        onepiece.push_back();
        onepiece.push_back();
        ans.push_back(onepiece);
        if(numRows == )
            return ans;

        //3...
        for(int row = ;row < numRows;row++)
        {
            onepiece.clear();
            for(int col = ;col <= row;col++)
            {
                if(col == || row == col)
                    onepiece.push_back();
                else
                onepiece.push_back(ans[row-][col-]+ans[row-][col]);
            }
            ans.push_back(onepiece);
        }
        return ans;
    }
};

int main()
{
    Solution mysolution;
    mysolution.generate();

    return ;
}