diff options
author | jack <[email protected]> | 2024-06-14 13:13:15 -0600 |
---|---|---|
committer | jack <[email protected]> | 2024-06-14 13:13:15 -0600 |
commit | d343a3b18dbaca9297d4f7b2280c4a16f0a5c8aa (patch) | |
tree | 96df922dae2a5073d9a50ea70c7aae6aa37e3ebe /eval_reverse_polish_notation.cpp | |
download | leetcode-d343a3b18dbaca9297d4f7b2280c4a16f0a5c8aa.tar.gz leetcode-d343a3b18dbaca9297d4f7b2280c4a16f0a5c8aa.zip |
initial
Diffstat (limited to 'eval_reverse_polish_notation.cpp')
-rw-r--r-- | eval_reverse_polish_notation.cpp | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/eval_reverse_polish_notation.cpp b/eval_reverse_polish_notation.cpp new file mode 100644 index 0000000..4cd39b8 --- /dev/null +++ b/eval_reverse_polish_notation.cpp @@ -0,0 +1,46 @@ +#include "leetcode.h" + +class Solution { +public: + int evalRPN(vector<string> &tokens) { + unordered_map<string, function<int(int, int)>> umf = { + {"+", [](long a, long b) { return a + b; }}, + {"-", [](long a, long b) { return a - b; }}, + {"*", [](long a, long b) { return a * b; }}, + {"/", [](long a, long b) { return a / b; }}}; + stack<long> stk; + for (string &s : tokens) { + if (!umf.count(s)) + stk.push(stoi(s)); + else { + long op1 = stk.top(); + stk.pop(); + long op2 = stk.top(); + stk.pop(); + stk.push(umf[s](op2, op1)); + } + } + return static_cast<int>(stk.top()); + } +}; + +int main() { + Solution obj; + vector<string> tokens1 = {"2", "1", "+", "3", "*"}; + // output: 9 + // ((2 + 1) * 3) + cout << obj.evalRPN(tokens1); + vector<string> tokens2 = {"4", "13", "5", "/", "+"}; + // output: 6 + // (4 + (13 / 5)) + cout << obj.evalRPN(tokens2); + vector<string> tokens3 = {"10", "6", "9", "3", "+", "-11", "*", + "/", "*", "17", "+", "5", "+"}; + // output: 22 + // ((10 * (6 / (12 * -11))) + 17) + 5 + // ((10 * (6 / -132)) + 17) + 5 + // ((10 * 0) + 17) + 5 + // (0 + 17) + 5 + // 17 + 5 + cout << obj.evalRPN(tokens3); +} |