_.Validate Stock Sequences
テーマの説明:
Given two sequences
Example 1:
Given two sequences
pushed
and popped
with distinct values、 return true
if and only if could have been the result of a sequence of push and pop operations on an initially empty stack.Example 1:
Input: pushed = [1,2,3,4,5], popped = [4,5,3,2,1]
Output: true
Explanation: We might do the following sequence:
push(1), push(2), push(3), push(4), pop() -> 4,
push(5), pop() -> 5, pop() -> 3, pop() -> 2, pop() -> 1
Example 2:Input: pushed = [1,2,3,4,5], popped = [4,3,5,1,2]
Output: false
Explanation: 1 cannot be popped before 2.
ノート:0 <= pushed.length == popped.length <= 1000
0 <= pushed[i], popped[i] < 1000
pushed
is a permutation of popped
.pushed
and popped
have distinct values.class Solution {
public:
bool validateStackSequences(vector& pushed, vector& popped) {
int i = 0, j = 0;
stack s;
while (i < pushed.size() && j < popped.size()) {
if (s.empty() || s.top() != popped[j]) {
s.push(pushed[i]);
i++;
}
else {
s.pop();
j++;
}
}
while (!s.empty() && s.top() == popped[j]) {
s.pop();
j++;
}
return i == pushed.size() && j == popped.size();
}
};