vector subscript out of range数组下标越界错误「建议收藏」

vector<vector<int> > myvec(n, vector<int>(n, 0));

//构造杨辉三角
class Solution { 

public:
vector<vector<int>> generate(int numRows) { 

vector<vector<int>> res(numRows);
if (numRows < 1) return res;
for (int i = 0; i < numRows; i++)
{ 

for (int j = 0; j <= i; j++)
{ 

if (j == 0 || j == i)
res[i][j] = 1;
else
res[i][j] = res[i - 1][j - 1] + res[i - 1][j];
}
}
return res;
}
};

//构造杨辉三角
class Solution { 

public:
vector<vector<int>> generate(int numRows) { 

vector<vector<int>> res(numRows);
if (numRows < 1) return res;
for (int i = 0; i < numRows; i++)
{ 

for (int j = 0; j <= i; j++)
{ 

if (j == 0 || j == i)
res[i].push_back(1);
else
res[i].push_back(res[i - 1][j - 1] + res[i - 1][j]);
}
}
return res;
}
};