diff --git a/CMakeLists.txt b/CMakeLists.txt
index fd4135c..e97679f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -31,4 +31,8 @@ add_executable(Playground
         csp-awarding/main.cc
         holiday-plan/main.cc
         bears-fruit-basket/main.cc
-        pre-sum/main.cc)
+        pre-sum/main.cc
+        trip-bus/main.cc
+        processing-parts/main.cc
+        logical-expressions/main.cc
+        logical-expressions/main.cc)
diff --git a/logical-expressions/data.in b/logical-expressions/data.in
new file mode 100644
index 0000000..f7d4402
--- /dev/null
+++ b/logical-expressions/data.in
@@ -0,0 +1 @@
+0&(1|0)|(1|1|1&0)
diff --git a/logical-expressions/main.cc b/logical-expressions/main.cc
new file mode 100644
index 0000000..74d88c2
--- /dev/null
+++ b/logical-expressions/main.cc
@@ -0,0 +1,91 @@
+#include <iostream>
+#include <stack>
+#include <vector>
+
+using namespace std;
+
+string expr;
+
+vector<char> expr_builder;
+stack<char> op_builder;
+
+void in_order2post_order() {
+    for (char ele: expr) {
+        if (ele == '0' || ele == '1')expr_builder.push_back(ele);
+        else if (ele == '(')op_builder.push(ele);
+        else if (ele == ')') {
+            while (!op_builder.empty() && op_builder.top() != '(') {
+                expr_builder.push_back(op_builder.top());
+                op_builder.pop();
+            }
+            op_builder.pop();
+        } else if (ele == '&') {
+            while (!op_builder.empty() && op_builder.top() == '&') {
+                expr_builder.push_back(op_builder.top());
+                op_builder.pop();
+            }
+            op_builder.push('&');
+        } else if (ele == '|') {
+            while (!op_builder.empty() && op_builder.top() != '(') {
+                expr_builder.push_back(op_builder.top());
+                op_builder.pop();
+            }
+            op_builder.push('|');
+        }
+    }
+    while (!op_builder.empty()) {
+        expr_builder.push_back(op_builder.top());
+        op_builder.pop();
+    }
+}
+
+const int N = 1e6 + 5;
+
+struct node {
+    int v, left, right;
+} ast[N];
+
+int plant_tree() {
+    int idx = 0;
+    stack<int> st;
+    for (auto item: expr_builder) {
+        if (isdigit(item)) {
+            ast[++idx] = {item - '0', -1, -1};
+            st.push(idx);
+        } else {
+            int right = st.top();
+            st.pop();
+            int left = st.top();
+            st.pop();
+            ast[++idx] = {(item == '&' ? 2 : 3), left, right};
+            st.push(idx);
+        }
+    }
+    return idx;
+}
+
+int short_circuit_and = 0, short_circuit_or = 0;
+
+int calc(int start) {
+    // Digit
+    if (ast[start].v == 0 || ast[start].v == 1) return ast[start].v;
+    // Operator
+    int left = calc(ast[start].left);
+    if (left == 0 && ast[start].v == 2) { // AND operator
+        short_circuit_and++;
+        return 0;
+    } else if (left == 1 && ast[start].v == 3) { // OR operator
+        short_circuit_or++;
+        return 1;
+    }
+    int right = calc(ast[start].right);
+    return right;
+}
+
+int main() {
+    cin >> expr;
+    in_order2post_order();
+    int start = plant_tree();
+    cout << calc(start) << endl;
+    printf("%d %d\n", short_circuit_and, short_circuit_or);
+}
\ No newline at end of file
diff --git a/processing-parts/data.in b/processing-parts/data.in
new file mode 100644
index 0000000..cbc6493
--- /dev/null
+++ b/processing-parts/data.in
@@ -0,0 +1,9 @@
+3 2 6
+1 2
+2 3
+1 1
+2 1
+3 1
+1 2
+2 2
+3 2
diff --git a/processing-parts/main.cc b/processing-parts/main.cc
new file mode 100644
index 0000000..0ad51ed
--- /dev/null
+++ b/processing-parts/main.cc
@@ -0,0 +1,60 @@
+#include <iostream>
+#include <cstring>
+
+using namespace std;
+
+const int MAXN = 10005;
+
+vector<int> graph[MAXN];
+bool visited[MAXN];
+int dis_odd[MAXN], dis_even[MAXN];
+
+void find_shortest_path() {
+    memset(dis_even, 0x3f, sizeof dis_even);
+    memset(dis_odd, 0x3f, sizeof dis_odd);
+    queue<pair<int, int>> q;
+    for (int &i: graph[1]) {
+        dis_odd[i] = 1;
+        q.emplace(i, 1);
+    }
+    while (!q.empty()) {
+        int x = q.front().first, y = q.front().second;
+        for (int &i: graph[x]) {
+            if (y % 2 == 0) {
+                if (y + 1 < dis_odd[i]) {
+                    dis_odd[i] = y + 1;
+                    q.emplace(i, y + 1);
+                }
+            } else {
+                if (y + 1 < dis_even[i]) {
+                    dis_even[i] = y + 1;
+                    q.emplace(i, y + 1);
+                }
+            }
+        }
+        q.pop();
+    }
+}
+
+int main() {
+    int n, m, q;
+    cin >> n >> m >> q;
+    for (int i = 0; i < m; i++) {
+        int u, v;
+        cin >> u >> v;
+        graph[u].push_back(v);
+        graph[v].push_back(u);
+    }
+    find_shortest_path();
+    while (q--) {
+        int u, v;
+        cin >> u >> v;
+        if (v % 2 == 0) {
+            if (dis_even[u] > v) cout << "No" << endl;
+            else cout << "Yes" << endl;
+        } else {
+            if (dis_odd[u] > v) cout << "No" << endl;
+            else cout << "Yes" << endl;
+        }
+    }
+}
\ No newline at end of file
diff --git a/trip-bus/main.cc b/trip-bus/main.cc
new file mode 100644
index 0000000..2fa15c4
--- /dev/null
+++ b/trip-bus/main.cc
@@ -0,0 +1,53 @@
+#include <iostream>
+#include <vector>
+#include <queue>
+#include <cstring>
+
+using namespace std;
+
+int dp[10005][105];
+bool visited[10005][105];
+
+struct node {
+    node(int i, int i1, int i2) {
+        this->u = i;
+        this->idx = i1;
+        this->d = i2;
+    }
+
+    int u, idx, d;
+
+    bool operator<(const node &other) const {
+        return d > other.d;
+    }
+};
+
+vector<pair<int, int>> graph[10005];
+
+int main() {
+    int n, m, k;
+    cin >> n >> m >> k;
+    for (int i = 0; i < m; i++) {
+        int u, v, a;
+        cin >> u >> v >> a;
+        graph[u].emplace_back(v, a);
+    }
+    memset(dp, 0x3f, sizeof dp);
+    priority_queue<node> tasks;
+    tasks.emplace(1, 0, dp[1][0] = 0);
+    while (!tasks.empty()) {
+        int u = tasks.top().u;
+        int idx = tasks.top().idx;
+        tasks.pop();
+        if (visited[u][idx]) continue;
+        else visited[u][idx] = true;
+        for (auto [v, w]: graph[u]) {
+            int time = dp[u][idx];
+            int j = (idx + 1) % k;
+            if (time < w) time += (w - time + k - 1) / k * k;
+            if (dp[v][j] > time + 1) tasks.emplace(v, j, dp[v][j] = time + 1);
+        }
+    }
+    if (dp[n][0] == 0x3f3f3f3f) dp[n][0] = 1;
+    cout << dp[n][0] << endl;
+}
\ No newline at end of file