diff options
Diffstat (limited to 'valid_stack_seq.cpp')
-rw-r--r-- | valid_stack_seq.cpp | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/valid_stack_seq.cpp b/valid_stack_seq.cpp new file mode 100644 index 0000000..62250db --- /dev/null +++ b/valid_stack_seq.cpp @@ -0,0 +1,32 @@ +// 946. Validate Stack Sequences +#include "leetcode.h" + +/* + * given two integer arrays 'pushed' & 'popped' each with distinct + * values, return true if this could have been the result of a sequence + * of push and pop operations on an initially empty stack, or false otherwise + */ + +class Solution { +public: + bool validateStackSequences(vector<int> &pushed, vector<int> &popped) { + stack<int> s; + int i = 0; + for (int x : pushed) { + s.push(x); + while (s.size() && s.top() == popped[i]) { + s.pop(); + i++; + } + } + return !s.size(); + } +}; + +int main() { + Solution obj; + vector<int> pushed = {1, 2, 3, 4, 5}; + vector<int> p1 = {4, 5, 3, 2, 1}, p2 = {4, 3, 5, 1, 2}; + printf("%d\n", obj.validateStackSequences(pushed, p1)); // expect: 1 + printf("%d\n", obj.validateStackSequences(pushed, p2)); // expect: 0 +} |