fix: fixed some utils.

Author: a1fredbao

src/alfred/algorithm/utils.hpp

@@ -7,13 +7,21 @@
 #include <vector>
 
 template <class T>
-inline void chkmax(T &x, T y) {
-    if (x < y) x = y;
+inline bool chkmax(T &x, T y) {
+    if (x < y) {
+        x = y;
+        return true;
+    }
+    return false;
 }
 
 template <class T>
-inline void chkmin(T &x, T y) {
-    if (x > y) x = y;
+inline bool chkmin(T &x, T y) {
+    if (x > y) {
+        x = y;
+        return true;
+    }
+    return false;
 }
 
 template <class T>

src/alfred/all

@@ -62,6 +62,9 @@ inline void Yes_No(bool cond) { cond ? Yes() : No(); }
 
 std::ostream &operator<<(std::ostream &os, i128 n) {
     std::string s;
+    if (n == 0) {
+        return os << "0";
+    }
     if (n < 0) {
         os << '-', n = -n;
     }

src/alfred/math/utils.hpp

@@ -32,6 +32,26 @@ inline T isqrt(T x) {
     return res;
 }
 
+using i128 = __int128;
+
+template <>
+inline i128 isqrt<i128>(i128 x) {
+    i128 L = 0, R = 13043817825332782ll, mid;
+    while (L < R) {
+        mid = (L + R + 1) >> 1;
+        if (mid * mid > x) {
+            R = mid - 1;
+        } else {
+            L = mid;
+        }
+    }
+    return L;
+}
+
+inline i128 abs128(i128 x) {
+    return x < 0 ? -x : x;
+}
+
 template <class T, class V>
 inline bool in_range(V v, T l, T r) {
     return l <= v && v <= r;

src/alfred/string/hashed-string.hpp

@@ -55,14 +55,14 @@ struct SingleHash {
 };
 
 struct HashedString {
-    using SH1 = SingleHash<
+    SingleHash<
         ctrandom::MOD_POOL[ctrandom::pick_idx1()],
-        ctrandom::SEED_POOL[ctrandom::pick_idx1()]>;
-    using SH2 = SingleHash<
+        ctrandom::SEED_POOL[ctrandom::pick_idx1()]>
+        H1;
+    SingleHash<
         ctrandom::MOD_POOL[ctrandom::pick_idx2()],
-        ctrandom::SEED_POOL[ctrandom::pick_idx2()]>;
-    SH1 H1;
-    SH2 H2;
+        ctrandom::SEED_POOL[ctrandom::pick_idx2()]>
+        H2;
     HashedString(void) = default;
     HashedString(std::string s) : H1(s), H2(s) {}
     inline void init(std::string s) {