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Luogu/P_1015_NOIP_1999_普及组_回文数.cpp

@@ -0,0 +1,58 @@
+#include <bits/stdc++.h>
+#define int long long
+#define endl "\n"
+#define IMX LONG_LONG_MAX
+#define IMN LONG_LONG_MIN
+#define debug$ if (dev)
+using namespace std;
+
+/* toothless. #17 */
+
+const int N = 1e7 + 10;
+const int M = 2e3 + 5;
+const bool dev = false;
+
+char s[M];
+int a[M], top;
+bool check()
+{
+    int t = top / 2;
+    for (int i = 0; i <= t; ++i)
+        if (a[i] != a[top - i])
+            return true;
+    return false;
+}
+
+signed main()
+{
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+    cout.tie(0);
+    int n, step = 0;
+    cin >> n >> s;
+    top = strlen(s) - 1;
+    for (int i = 0; i <= top; ++i)
+        if (s[i] >= '0' && s[i] <= '9')
+            a[top - i] = s[i] - '0';
+        else
+            a[top - i] = s[i] - 55;
+    while (check()) {
+        if (step > 30) {
+            cout << "Impossible!";
+            return 0;
+        }
+        for (int i = 0; i <= top; ++i)
+            if (top - i >= i)
+                a[i] += a[top - i];
+            else
+                a[i] = a[top - i];
+        for (int i = 0; i <= top; ++i)
+            if (a[i] >= n)
+                a[i + 1]++, a[i] -= n;
+        if (a[top + 1])
+            top++;
+        step++;
+    }
+    cout << "STEP=" << step;
+    return 0;
+}

Luogu/P_10446_64_位整数乘法.cpp

@@ -0,0 +1,34 @@
+#include <bits/stdc++.h>
+#define lo long long
+#define IMX LONG_LONG_MAX
+#define IMN LONG_LONG_MIN
+
+using namespace std;
+const int N = 1e7 + 10;
+/*
+    toothless. #17
+    @fredcss_dev
+*/
+
+lo qpow(lo a, lo b, lo p) {
+    lo result = 0;
+    while (b) {
+        if (b & 1) {
+            result += a;
+            result %= p;
+        }
+        b >>= 1;
+        a += a;
+        a %= p;
+    }
+    return result;
+}
+
+lo a, b, p; 
+
+signed main()
+{
+	cin >> a >> b >> p;
+	cout << qpow(a, b, p);
+    return 0;
+}

Luogu/P_1060_NOIP_2006_普及组_开心的金明.cpp

@@ -0,0 +1,27 @@
+#include <bits/stdc++.h>
+#define lo long long
+#define IMX LONG_LONG_MAX
+#define IMN LONG_LONG_MIN
+
+using namespace std;
+const int N = 1e7 + 10;
+/*
+    toothless. #17
+    @fredcss_dev
+    <2025/1/21>
+*/
+
+int m, n, d[N], w, v;
+
+signed main()
+{
+	cin >> m >> n;
+    for(int i = 1; i <= n; i++) {
+        cin >> v >> w;
+        for(int j = m; j >= v; j--){
+            d[j] = max(d[j], d[j - v] + w * v);
+        }
+    }
+    printf("%d",d[m]);
+    return 0;
+}

Luogu/P_1135_奇怪的电梯.cpp

@@ -0,0 +1,49 @@
+#include <bits/stdc++.h>
+#define int long long
+#define endl "\n"
+#define IMX LONG_LONG_MAX
+#define IMN LONG_LONG_MIN
+#define debug$ if(dev)
+using namespace std;
+
+/* toothless. #17 */
+
+const int N = 1e7 + 10;
+const int M = 2e3 + 5;
+const bool dev = false;
+
+int n, k;
+int a[N];
+int ans=0;
+
+bool isPrime(int x)
+{
+    if (x == 1)
+        return false;
+    for (int i = 2; i * i <= x; i++)
+        if (x % i == 0)
+            return false;
+    return true;
+}
+
+void dfs(int x, int sum, int cnt)
+{
+    if (x == k) {
+        if (isPrime(sum))
+            ans++;
+        return;
+    }
+    for (int i = cnt; i < n; i++) {
+        dfs(x + 1, sum + a[i], i + 1);
+    }
+}
+
+signed main()
+{
+    cin >> n;
+    for (int i = 1; i <= n; i++)
+        cin >> a[i];
+    dfs(0, 0, 0);
+    cout << ans << endl;
+    return 0;
+}`