upload some new code

FZOI/Fibonacci 前n项和.cpp

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+#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, m;
+int sum = 0;
+
+struct node
+{
+    int mat[4][4];
+};
+
+node z;
+
+node matrix_nul(node x, node y)
+{
+    memset(z.mat, 0, sizeof(z.mat));
+    for(int i = 1; i <= 3; i ++ )
+    {
+        for(int j = 1; j <= 3; j ++ )
+        {
+            for(int k = 1; k <= 3; k ++ )
+            {
+                z.mat[i][j] += (x.mat[i][k]) % m * (y.mat[k][j]) % m;
+                z.mat[i][j] %= m;
+            }
+        }
+    }
+    return z;
+}
+
+node matrix_pow(int k)
+{
+    node t, a;
+    t.mat[1][1] = 1;
+    t.mat[1][2] = 1;
+    t.mat[1][3] = 1;
+    a.mat[1][1]=1;
+	a.mat[1][2]=0;
+	a.mat[1][3]=0;
+	a.mat[2][1]=1;
+	a.mat[2][2]=1;
+	a.mat[2][3]=1;
+	a.mat[3][1]=0;
+	a.mat[3][2]=1;
+	a.mat[3][3]=0;
+    while(k)
+    {
+        if(k % 2 == 1) t = matrix_nul(t, a);
+        k /= 2;
+        a = matrix_nul(a, a);
+    }
+    return t;
+}
+
+signed main()
+{
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+    cout.tie(0);
+    cin >> n >> m ;
+    node temp;
+    temp = matrix_pow(n - 1);
+    int ans = temp.mat[1][1] * 1 + temp.mat[2][1] * 0;
+    ans %= m;
+    cout << ans % m ;
+    return 0;
+}