diff --git a/QUSTOJ/1650.cpp b/QUSTOJ/1650.cpp
new file mode 100644
index 0000000..7ed0eb3
--- /dev/null
+++ b/QUSTOJ/1650.cpp
@@ -0,0 +1,82 @@
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+using namespace std;
+
+//Kiritow's BIGN (class BigNumber) Written on Nov. 12th, 2015
+//Original Version: Build 1
+class bign
+{
+public:
+    //WARNING: We use public here to reduce time consumed on Interface, although this is not a recommended way.
+    int data[3000];
+    bool more_than_zero;
+    bign()
+    {
+        more_than_zero=true;
+    }
+    void set_empty()
+    {
+        memset(data,0,sizeof(int)*3000);
+    }
+    int lenx()
+    {
+        for(int i=3000-1;i>=0;i--)
+        {
+            if(data[i]!=0) return i+1;
+        }
+        return 0;
+    }
+};
+
+char CompareBIGN(bign& a,bign& b)
+{
+    int lena=a.lenx();
+    int lenb=b.lenx();
+    if(lena<lenb)
+    {
+        return '<';
+    }
+    else if (lena>lenb)
+    {
+        return '>';
+    }
+    else
+    {
+        for(int i=lena-1;i>=0;i--)
+        {
+            if(a.data[i]>b.data[i])
+            {
+                return '>';
+            }
+            else if(a.data[i]<b.data[i])
+            {
+                return '<';
+            }
+        }
+        return '=';
+    }
+}
+
+void ConvertSTRtoBIGN(const char* incstr,bign& incbign)
+{
+    int len=strlen(incstr);
+    for(int i=0;i<len;i++)
+    {
+        incbign.data[len-i-1]=incstr[i]-'0';
+    }
+}
+
+bign a,b;
+char buff[3000];
+int main()
+{
+    a.set_empty();
+    b.set_empty();
+    gets(buff);
+    ConvertSTRtoBIGN(buff,a);
+    gets(buff);
+    ConvertSTRtoBIGN(buff,b);
+    printf("%c\n",CompareBIGN(a,b));
+    return 0;
+}
diff --git a/QUSTOJ/1651.cpp b/QUSTOJ/1651.cpp
new file mode 100644
index 0000000..917f2c8
--- /dev/null
+++ b/QUSTOJ/1651.cpp
@@ -0,0 +1,66 @@
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+using namespace std;
+
+//Kiritow's BIGN (class BigNumber) Written on Nov. 12th, 2015
+//Original Version: Build 1 (Version 2)
+//CCBIGN : from BIGN (Build 1 -version 2)
+class ccbign
+{
+public:
+    //WARNING: We use public here to reduce time consumed on Interface, although this is not a recommended way
+    int data[3000];
+    int length;
+    ccbign()
+    {
+        length=0;
+    }
+    void set_empty()
+    {
+        memset(data,0,sizeof(int)*3000);
+    }
+};
+
+int ConvertSTRtoCCBIGN(const char* incstr,ccbign& incbign)
+{
+    int len=strlen(incstr);
+    for(int i=0;i<len;i++)
+    {
+        incbign.data[i]=incstr[i]-'0';
+    }
+    incbign.length=len;
+    return len;
+}
+
+ccbign a;
+
+char buff[3000];
+
+int main()
+{
+    int times;
+    scanf("%d%*c",&times);
+    for(;times>0;times--)
+    {
+        a.set_empty();
+        gets(buff);
+        int len=ConvertSTRtoCCBIGN(buff,a);
+        for(int i=0;i<len-1;i++)
+        {
+            int tmp=a.data[i]*10+a.data[i+1];
+            if(tmp<17)
+            {
+                a.data[i+1]+=a.data[i]*10;
+                continue;
+            }
+            else
+            {
+                a.data[i+1]=tmp%17;
+            }
+        }
+        int answer=a.data[a.length-1];
+        printf("%d\n",answer);
+    }
+    return 0;
+}
diff --git a/ZOJ/3936.cpp b/ZOJ/3936.cpp
new file mode 100644
index 0000000..d60db38
--- /dev/null
+++ b/ZOJ/3936.cpp
@@ -0,0 +1,18 @@
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+using namespace std;
+
+int main()
+{
+    int t;
+    scanf("%d",&t);
+    while(t--)
+    {
+        int a,b,c,d;
+        scanf("%d %d %d %d",&a,&b,&c,&d);
+        printf("%d %d\n",c,b+d);
+        printf("%d %d\n",a,b+d);
+    }
+    return 0;
+}
diff --git a/ZOJ/3937_csdn.cpp b/ZOJ/3937_csdn.cpp
new file mode 100644
index 0000000..5599d4e
--- /dev/null
+++ b/ZOJ/3937_csdn.cpp
@@ -0,0 +1,98 @@
+#include <bits/stdc++.h>
+using namespace std;
+typedef long long LL;
+
+class Solution {
+  static const int MAXN = 100000 + 10;
+  static const LL inf = 1ll << 60;
+  vector<int> G[MAXN];
+  int w[MAXN], n;
+
+  struct Line {// m * x + b
+    LL m, b;
+    double inter(const Line &r) const {
+      return (r.b - b) / (m - r.m);
+    }
+    inline LL eval(LL x) {return m * x + b;}
+  } Q[MAXN];a
+
+  int rt, mins, total, top;
+  int vs[MAXN], sz[MAXN], dep[MAXN];
+  LL val[MAXN], ps[MAXN], ret;
+
+  void getCenter(int u, int f = -1) {
+    int mx = 0; sz[u] = 1;
+    for (auto &v: G[u]) if (v != f && !vs[v]) {
+      getCenter(v, u); sz[u] += sz[v];
+      mx = max(mx, sz[v]);
+    }
+    mx = max(mx, total - sz[u]);
+    if (mx < mins) mins = mx, rt = u;
+  }
+  int dfs1(int u, int d = 1) {
+    ret = max(ret, val[d]);
+    for (auto &v: G[u]) if (!vs[v] && u > v) {
+      ps[v] = ps[u] + w[v];
+      val[d + 1] = val[d] + ps[v];
+      return dfs1(v, d + 1) + 1;
+    }
+    return 1;
+  }
+  void dfs2(int u, int d = 0, LL sum = 0) {
+    sum += 1ll * d * w[u];
+    // max(ps[u] * m + b + sum)
+    int left = 0, right = top - 2;
+    while (left < right) {
+      int mid = (left + right) >> 1;
+      if (Q[mid].eval(ps[u]) >= Q[mid + 1].eval(ps[u])) right = mid;
+      else left = mid + 1;
+    }
+    ret = max(ret, Q[left].eval(ps[u]) + sum);
+    if (left + 1 < top) ret = max(ret, Q[left + 1].eval(ps[u]) + sum);
+    for (auto &v: G[u]) if (!vs[v] && u < v) {
+      ps[v] = ps[u] + w[v];
+      dfs2(v, d + 1, sum);
+    }
+  }
+  void solve(int u, int _tot) {
+    total = _tot; mins = _tot * 2;
+    getCenter(u); u = rt; vs[u] = 1; getCenter(u);
+    val[1] = ps[u] = w[u];
+    int md = dfs1(u);
+    top = 0;
+    for (int i = 1; i <= md; ++i) {
+      Line now = (Line){i, val[i]};
+      while (top >= 2 && Q[top - 2].inter(Q[top - 1]) >= Q[top - 1].inter(now)) --top;
+      Q[top++] = now;
+    }
+    ps[u] = 0; dfs2(u);
+    for (int i = 0; i <= md; ++i) val[i] = -inf;
+    for (auto &v: G[u]) if (!vs[v]) {
+      solve(v, sz[v]);
+    }
+  }
+
+public:
+  void run() {
+    scanf("%d", &n);
+    for (int i = 0; i < n; ++i) {
+      scanf("%d", w + i); G[i].clear();
+    }
+    for (int i = 1; i < n; ++i) {
+      int x; scanf("%d", &x); --x;
+      G[x].push_back(i);
+      G[i].push_back(x);
+    }
+    ret = 0;
+    for (int i = 0; i < n; ++i) val[i] = -inf;
+    memset(vs, 0, sizeof(vs[0]) * n);
+    solve(0, n);
+    printf("%lld\n", ret);
+  }
+} sol;
+
+int main() {
+  int T; scanf("%d", &T);
+  for (int cas = 1; cas <= T; ++cas) sol.run();
+  return 0;
+}
diff --git a/ZOJ/3938_csdn.cpp b/ZOJ/3938_csdn.cpp
new file mode 100644
index 0000000..c2e9989
--- /dev/null
+++ b/ZOJ/3938_csdn.cpp
@@ -0,0 +1,49 @@
+#include <bits/stdc++.h>
+using namespace std;
+typedef pair<int, int> PII;
+
+vector<PII> res;
+int b[5][5], a[5];
+
+int main() {
+  int T; scanf("%d", &T);
+  for (int cas = 1; cas <= T; ++cas) {
+    int r[5];
+    for (int i = 0; i < 5; ++i) {
+      for (int j = 0; j < 5; ++j) {
+        cin >> b[i][j];
+      }
+    }
+    // stage 1
+    int *x = b[0], d = x[0];
+    if (d <= 2) r[0] = 2;
+    else r[0] = d;
+    // stage 2
+    x = b[1], d = x[0];
+    for (int i = 1; i < 5; ++i) a[x[i]] = i;
+    if (d == 1) r[1] = a[4];
+    else if (d == 3) r[1] = 1;
+    else r[1] = r[0];
+    // stage 3
+    x = b[2], d = x[0];
+    for (int i = 1; i < 5; ++i) a[x[i]] = i;
+    if (d == 1) r[2] = a[b[1][r[1]]];
+    else if (d == 2) r[2] = a[b[0][r[0]]];
+    else if (d == 4) r[2] = a[4];
+    else r[2] = d;
+    // stage 4
+    x = b[3], d = x[0];
+    if (d == 1) r[3] = r[0];
+    else if (d == 2) r[3] = 1;
+    else r[3] = r[1];
+    // stage 5
+    x = b[4], d = x[0];
+    for (int i = 1; i < 5; ++i) a[x[i]] = i;
+    if (d <= 2) r[4] = a[b[d - 1][r[d - 1]]];
+    else r[4] = a[b[6 - d][r[6 - d]]];
+    for (int i = 0; i < 5; ++i) {
+      cout << r[i] << " " << b[i][r[i]] << endl;
+    }
+  }
+  return 0;
+}
diff --git a/ZOJ/3939_csdn.cpp b/ZOJ/3939_csdn.cpp
new file mode 100644
index 0000000..bda31ba
--- /dev/null
+++ b/ZOJ/3939_csdn.cpp
@@ -0,0 +1,37 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+vector<tuple<int, int, int>> p;
+
+int day(int y, int m, int d) {
+  int tm = m >= 3 ? (m - 2) : (m + 10);
+  int ty = m >= 3 ? y : (y - 1);
+  return (ty + ty / 4 - ty / 100 + ty / 400 + (int)(2.6 * tm - 0.2) + d) % 7;
+}
+
+void run() {
+  int y, m, d, n; cin >> y >> m >> d >> n;
+  y -= 1753; n += y / 2800 * p.size();
+  y %= 2800;
+  n += lower_bound(p.begin(), p.end(), make_tuple(y, m, d)) - p.begin() - 1;
+  auto res = p[n % p.size()];
+  y = get<0>(res);
+  m = get<1>(res);
+  d = get<2>(res);
+  y += n / p.size() * 2800 + 1753;
+  cout << y << " " << m << " " << d << endl;
+}
+
+int main() {
+  cerr << day(1753, 1, 1) << endl;
+  for (int y = 0; y < 2800; ++y) {
+    for (int m = 1; m <= 12; ++m) {
+      if (day(y + 1753, m,  1) == 1) p.push_back(make_tuple(y, m,  1));
+      if (day(y + 1753, m, 11) == 1) p.push_back(make_tuple(y, m, 11));
+      if (day(y + 1753, m, 21) == 1) p.push_back(make_tuple(y, m, 21));
+    }
+  }
+  int T; scanf("%d", &T);
+  for (int cas = 1; cas <= T; ++cas) run();
+  return 0;
+}
diff --git a/ZOJ/3947.cpp b/ZOJ/3947.cpp
new file mode 100644
index 0000000..1c83639
--- /dev/null
+++ b/ZOJ/3947.cpp
@@ -0,0 +1,23 @@
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+using namespace std;
+
+int main()
+{
+    int t;
+    scanf("%d",&t);
+    while(t--)
+    {
+        int n,tmp,sum;
+        scanf("%d",&n);
+        sum=n;
+        for(int i=0;i<n;i++)
+        {
+            scanf("%d",&tmp);
+            sum+=tmp;
+        }
+        printf("%d\n",sum);
+    }
+    return 0;
+}