bzoj 1031

OnlineJudges/lydsy/1031.cpp

@@ -0,0 +1,54 @@
+#include <cstdio>
+#include <cstring>
+const int N = int(2e5 + 3);
+char str[N];
+int sa[N], rank[N], height[N], c[N];
+template <typename T>
+inline void swap(T &x, T &y)
+{
+    T t = x;
+    x = y;
+    y = t;
+}
+inline bool In_equal(const int *x, const int i, const int j, const int k, const int n)
+{
+    int ti = i + k < n ? x[i + k] : -1, tj = j + k < n ? x[j + k] : -1;
+    return x[i] == x[j] && ti == tj;
+}
+int main()
+{
+    scanf("%s", str);
+    int len = int(strlen(str));
+    memcpy(str + len, str, len);
+    len <<= 1;
+    int *x = rank, *y = height, r = 256, yn;
+    for (int i = 0; i < r; ++i) c[i] = 0;
+    for (int i = 0; i < len; ++i) ++c[str[i]];
+    for (int i = 1; i < r; ++i) c[i] += c[i - 1];
+    for (int i = len - 1; i >= 0; --i) sa[--c[str[i]]] = i;
+    r = 1;
+    x[sa[0]] = 0;
+    for (int i = 1; i < len; ++i)
+        x[sa[i]] = str[sa[i]] == str[sa[i - 1]] ? r - 1 : r++;
+    for (int k = 1; r < len; k <<= 1)
+    {
+        yn = 0;
+        for (int i = len - k; i < len; ++i) y[yn++] = i;
+        for (int i = 0; i < len; ++i)
+            if (sa[i] >= k) y[yn++] = sa[i] - k;
+        for (int i = 0; i < r; ++i) c[i] = 0;
+        for (int i = 0; i < len; ++i) ++c[x[y[i]]];
+        for (int i = 1; i < r; ++i) c[i] += c[i - 1];
+        for (int i = len - 1; i >= 0; --i) sa[--c[x[y[i]]]] = y[i];
+        swap(x, y);
+        r = 1;
+        x[sa[0]] = 0;
+        for (int i = 1; i < len; ++i)
+            x[sa[i]] = In_equal(y, sa[i], sa[i - 1], k, len) ? r - 1 : r++;
+    }
+    for (int i = 0; i < len; ++i) rank[i] = x[i];
+    for (int i = 0; i < len; i++)
+        if (sa[i] < len >> 1)
+            putchar(str[sa[i] + (len >> 1) - 1]);
+    return 0;
+}