[LeetCode]118. Pascal's Triangle

[LeetCode]118. Pascal’s Triangle

题目描述

思路

代码

#include <iostream>
#include <vector>

using namespace std;

class Solution {
public:
vector<vector<int>> generate(int numRows) {
/*
vector<vector<int>> res;
for (int i = 0; i < numRows; ++i) {
vector<int> temp;
if (i < 2)
for (int j = 0; j <= i; ++j)
temp.push_back(1);
else {
int left = 0, right = 1;
for (int j = 0; j <= i; ++j) {
if (j == 0 || j == i)
temp.push_back(1);
else
temp.push_back(res[i - 1][left++] + res[i - 1][right++]);
}
}
res.push_back(temp);
}
return res;
*/
vector<vector<int>> res(numRows);
for (int i = 0; i < numRows; ++i) {
res[i].resize(i + 1);
res[i][0] = 1;
res[i][i] = 1;

for (int j = 1; j < i; ++j) {
res[i][j] = res[i - 1][j - 1] + res[i - 1][j];
}
}
return res;
}
};

int main() {
vector<vector<int>> res;
Solution s;
res = s.generate(5);

for (auto vec : res) {
for (int num : vec)
cout << num << " ";
cout << endl;
}

system("pause");
return 0;
}