diff --git a/OnlineJudges/lydsy/1412.cpp b/OnlineJudges/lydsy/1412.cpp
new file mode 100644
index 0000000..728960c
--- /dev/null
+++ b/OnlineJudges/lydsy/1412.cpp
@@ -0,0 +1,100 @@
+#include <cstdio>
+#include <cstring>
+inline int min(int a, int b) { return a < b ? a : b; }
+const int maxn = 10010, maxm = 100005, inf = 0x3f3f3f3f;
+int head[maxn], next[maxm], to[maxm], cap[maxm], ecnt, cnt, a[110][110];
+int num[maxn], dis[maxn], fa[maxn], que[maxm], cur[maxn];
+int dx[] = { 0, 1, 0, -1 };
+int dy[] = { 1, 0, -1, 0 };
+inline void addEdge_impl_(int f, int t, int c)
+{
+    next[ecnt] = head[f];
+    head[f] = ecnt;
+    to[ecnt] = t;
+    cap[ecnt] = c;
+    ecnt++;
+}
+inline void addEdge(int f, int t, int c)
+{
+    addEdge_impl_(f, t, c);
+    addEdge_impl_(t, f, 0);
+}
+int ISAP(int s, int e)
+{
+    int flow = 0;
+    int h = 0, t = 0, x;
+    for (int i = 0; i <= cnt; i++) dis[i] = cnt;
+    dis[que[t++] = e] = 0;
+    while (h != t) for (int i = head[x = que[h++]]; ~i; i = next[i])
+        if (cap[i ^ 1] > 0 && dis[to[i]] > dis[x] + 1)
+            dis[que[t++] = to[i]] = dis[x] + 1;
+    memset(num, 0, sizeof(num));
+    for (int i = 0; i <= cnt; i++) num[dis[i]]++, cur[i] = head[i];
+    x = s;
+    while (dis[s] < cnt)
+    {
+        if (x == e)
+        {
+            int curFlow = 0x3f3f3f3f;
+            for (x = e; x != s; x = to[fa[x] ^ 1])
+                curFlow = min(curFlow, cap[fa[x]]);
+            for (x = e; x != s; x = to[fa[x] ^ 1])
+                cap[fa[x]] -= curFlow, cap[fa[x] ^ 1] += curFlow;
+            flow += curFlow;
+            x = s;
+        }
+        bool needRetreat = true;
+        for (int i = cur[x]; needRetreat && ~i; i = next[i])
+            if (cap[i] && dis[to[i]] == dis[x] - 1)
+                needRetreat = false, cur[x] = i, fa[x = to[i]] = i;
+        if (needRetreat)
+        {
+            int mn = cnt - 1;
+            for (int i = head[x]; ~i; i = next[i])
+                if (cap[i]) mn = min(mn, dis[to[i]]);
+            if (--num[dis[x]] == 0) break;
+            num[dis[x] = mn + 1]++;
+            cur[x] = head[x];
+            if (x != s) x = to[fa[x] ^ 1];
+        }
+    }
+    return flow;
+}
+
+int main()
+{
+    memset(head, -1, sizeof(head));
+    int n, m;
+    scanf("%d%d", &n, &m);
+    int S = 0, T = n * m + 1;
+    cnt = T + 1;
+    for (int i = 1; i <= n; i++)
+        for (int j = 1; j <= m; j++)
+        {
+            scanf("%d", &a[i][j]);
+            if (a[i][j] == 1)
+                addEdge(S, (i - 1) * m + j, inf);
+            if (a[i][j] == 2)
+                addEdge((i - 1) * m + j, T, inf);
+        }
+    for (int i = 1; i <= n; i++)
+        for (int j = 1; j <= m; j++)
+        {
+            for (int k = 0; k < 4; k++)
+            {
+                int x = i + dx[k], y = j + dy[k];
+                if (x > n || x < 1 || y > m || y < 1)
+                    continue;
+                if (a[i][j] == 1)
+                    if (a[i][j] != a[x][y])
+                        addEdge((i - 1) * m + j, (x - 1) * m + y, 1);
+                if (a[i][j] == 2)
+                    if (a[x][y] == 0)
+                        addEdge((x - 1) * m + y, (i - 1) * m + j, 1);
+                if (a[i][j] == a[x][y] && a[i][j] == 0)
+                    addEdge((i - 1) * m + j, (x - 1) * m + y, 1);
+            }
+        }
+    printf("%d\n", ISAP(S, T));
+    return 0;
+}
\ No newline at end of file
diff --git a/OnlineJudges/lydsy/1497.cpp b/OnlineJudges/lydsy/1497.cpp
new file mode 100644
index 0000000..62eeeef
--- /dev/null
+++ b/OnlineJudges/lydsy/1497.cpp
@@ -0,0 +1,78 @@
+#include <cstdio>
+#include <cstring>
+inline int min(int a, int b) { return a < b ? a : b; }
+const int inf = 0x3f3f3f3f, maxn = 100010, maxm = maxn << 2;
+int head[maxn], next[maxm], to[maxm], cap[maxm], ecnt, cnt;
+int dis[maxn], cur[maxn], num[maxn], que[maxn], fa[maxn];
+inline void addEdge_impl_(int f, int t, int c)
+{
+    next[ecnt] = head[f];
+    head[f] = ecnt;
+    to[ecnt] = t;
+    cap[ecnt] = c;
+    ecnt++;
+}
+inline void addEdge(int f, int t, int c)
+{
+    addEdge_impl_(f, t, c);
+    addEdge_impl_(t, f, 0);
+}
+int ISAP(int s, int e)
+{
+    int h = 0, t = 0, x, flow = 0;
+    for (int i = 0; i <= cnt; i++) dis[i] = cnt;
+    dis[que[t++] = e] = 0;
+    while (h != t) for (int i = head[x = que[h++]]; ~i; i = next[i])
+        if (cap[i ^ 1] > 0 && dis[to[i]] > dis[x] + 1)
+            dis[que[t++] = to[i]] = dis[x] + 1;
+    memset(num, 0, sizeof(num));
+    for (int i = 0; i <= cnt; i++) num[dis[i]]++, cur[i] = head[i];
+    x = s;
+    while (dis[s] < cnt)
+    {
+        if (x == e)
+        {
+            int curFlow = inf;
+            for (x = e; x != s; x = to[fa[x] ^ 1]) curFlow = min(curFlow, cap[fa[x]]);
+            for (x = e; x != s; x = to[fa[x] ^ 1]) cap[fa[x]] -= curFlow, cap[fa[x] ^ 1] += curFlow;
+            flow += curFlow, x = s;
+        }
+        bool needRetreat = true;
+        for (int i = cur[x]; needRetreat && ~i; i = next[i])
+            if (cap[i] > 0 && dis[x] == dis[to[i]] + 1)
+                needRetreat = false, cur[x] = i, fa[x = to[i]] = i;
+        if (needRetreat)
+        {
+            int mn = cnt - 1;
+            for (int i = head[x]; ~i; i = next[i])
+                if (cap[i]) mn = min(mn, dis[to[i]]);
+            if (--num[dis[x]] == 0) break;
+            ++num[dis[x] = mn + 1];
+            cur[x] = head[x];
+            if (x != s) x = to[fa[x] ^ 1];
+        }
+    }
+    return flow;
+}
+int main()
+{
+    memset(head, -1, sizeof(head));
+    int n, m, sum = 0;
+    scanf("%d%d", &n, &m);
+    cnt = n + m + 2;
+    for (int i = 1, x; i <= n; i++)
+    {
+        scanf("%d", &x);
+        addEdge(0, i, x);
+    }
+    for (int i = 1, x, y, z; i <= m; i++)
+    {
+        scanf("%d%d%d", &x, &y, &z);
+        addEdge(x, n + i, inf);
+        addEdge(y, n + i, inf);
+        addEdge(n + i, n + m + 1, z);
+        sum += z;
+    }
+    printf("%d", sum - ISAP(0, n + m + 1));
+    return 0;
+}
\ No newline at end of file
diff --git a/OnlineJudges/lydsy/1934.cpp b/OnlineJudges/lydsy/1934.cpp
new file mode 100644
index 0000000..5ce1c5b
--- /dev/null
+++ b/OnlineJudges/lydsy/1934.cpp
@@ -0,0 +1,77 @@
+#include <cstdio>
+#include <cstring>
+inline int min(int a, int b) { return a < b ? a : b; }
+const int maxn = 310, maxm = maxn * maxn * 2, inf = 0x3f3f3f3f;
+int head[maxn], to[maxm], cap[maxm], next[maxm], ecnt;
+int dis[maxn], num[maxn], fa[maxn], que[maxn], cur[maxn], cnt;
+inline void addEdge_impl_(int f, int t, int c)
+{
+    next[ecnt] = head[f];
+    head[f] = ecnt;
+    to[ecnt] = t;
+    cap[ecnt] = c;
+    ecnt++;
+}
+inline void addEdge(int f, int t, int c)
+{
+    addEdge_impl_(f, t, c);
+    addEdge_impl_(t, f, 0);
+}
+int ISAP(int s, int e)
+{
+    int h = 0, t = 0, x, flow = 0;
+    for (int i = 0; i <= cnt; i++) dis[i] = cnt;
+    dis[que[t++] = e] = 0;
+    while (h != t) for (int i = head[x = que[h++]]; ~i; i = next[i])
+        if (cap[i ^ 1] > 0 && dis[to[i]] > dis[x] + 1)
+            dis[que[t++] = to[i]] = dis[x] + 1;
+    memset(num, 0, sizeof(num));
+    for (int i = 0; i <= cnt; i++) num[dis[i]]++, cur[i] = head[i];
+    x = s;
+    while (dis[s] < cnt)
+    {
+        if (x == e)
+        {
+            int curFlow = inf;
+            for (x = e; x != s; x = to[fa[x] ^ 1]) curFlow = min(curFlow, cap[fa[x]]);
+            for (x = e; x != s; x = to[fa[x] ^ 1]) cap[fa[x]] -= curFlow, cap[fa[x] ^ 1] += curFlow;
+            flow += curFlow, x = s;
+        }
+        bool needRetreat = true;
+        for (int i = cur[x]; needRetreat && ~i; i = next[i])
+            if (cap[i] > 0 && dis[x] == dis[to[i]] + 1)
+                needRetreat = false, cur[x] = i, fa[x = to[i]] = i;
+        if (needRetreat)
+        {
+            int mn = cnt - 1;
+            for (int i = head[x]; ~i; i = next[i])
+                if (cap[i]) mn = min(mn, dis[to[i]]);
+            if (--num[dis[x]] == 0) break;
+            ++num[dis[x] = mn + 1];
+            cur[x] = head[x];
+            if (x != s) x = to[fa[x] ^ 1];
+        }
+    }
+    return flow;
+}
+int main()
+{
+    memset(head, -1, sizeof(head));
+    int n, m;
+    scanf("%d%d", &n, &m);
+    cnt = n + 2;
+    for (int i = 1, x; i <= n; i++)
+    {
+        scanf("%d", &x);
+        if (x) addEdge(0, i, 1);
+        else addEdge(i, n + 1, 1);
+    }
+    for (int i = 1, x, y; i <= m; i++)
+    {
+        scanf("%d%d", &x, &y);
+        addEdge_impl_(x, y, 1);
+        addEdge_impl_(y, x, 1);
+    }
+    printf("%d", ISAP(0, n + 1));
+    return 0;
+}
\ No newline at end of file
diff --git a/OnlineJudges/lydsy/2768.cpp b/OnlineJudges/lydsy/2768.cpp
new file mode 100644
index 0000000..5ce1c5b
--- /dev/null
+++ b/OnlineJudges/lydsy/2768.cpp
@@ -0,0 +1,77 @@
+#include <cstdio>
+#include <cstring>
+inline int min(int a, int b) { return a < b ? a : b; }
+const int maxn = 310, maxm = maxn * maxn * 2, inf = 0x3f3f3f3f;
+int head[maxn], to[maxm], cap[maxm], next[maxm], ecnt;
+int dis[maxn], num[maxn], fa[maxn], que[maxn], cur[maxn], cnt;
+inline void addEdge_impl_(int f, int t, int c)
+{
+    next[ecnt] = head[f];
+    head[f] = ecnt;
+    to[ecnt] = t;
+    cap[ecnt] = c;
+    ecnt++;
+}
+inline void addEdge(int f, int t, int c)
+{
+    addEdge_impl_(f, t, c);
+    addEdge_impl_(t, f, 0);
+}
+int ISAP(int s, int e)
+{
+    int h = 0, t = 0, x, flow = 0;
+    for (int i = 0; i <= cnt; i++) dis[i] = cnt;
+    dis[que[t++] = e] = 0;
+    while (h != t) for (int i = head[x = que[h++]]; ~i; i = next[i])
+        if (cap[i ^ 1] > 0 && dis[to[i]] > dis[x] + 1)
+            dis[que[t++] = to[i]] = dis[x] + 1;
+    memset(num, 0, sizeof(num));
+    for (int i = 0; i <= cnt; i++) num[dis[i]]++, cur[i] = head[i];
+    x = s;
+    while (dis[s] < cnt)
+    {
+        if (x == e)
+        {
+            int curFlow = inf;
+            for (x = e; x != s; x = to[fa[x] ^ 1]) curFlow = min(curFlow, cap[fa[x]]);
+            for (x = e; x != s; x = to[fa[x] ^ 1]) cap[fa[x]] -= curFlow, cap[fa[x] ^ 1] += curFlow;
+            flow += curFlow, x = s;
+        }
+        bool needRetreat = true;
+        for (int i = cur[x]; needRetreat && ~i; i = next[i])
+            if (cap[i] > 0 && dis[x] == dis[to[i]] + 1)
+                needRetreat = false, cur[x] = i, fa[x = to[i]] = i;
+        if (needRetreat)
+        {
+            int mn = cnt - 1;
+            for (int i = head[x]; ~i; i = next[i])
+                if (cap[i]) mn = min(mn, dis[to[i]]);
+            if (--num[dis[x]] == 0) break;
+            ++num[dis[x] = mn + 1];
+            cur[x] = head[x];
+            if (x != s) x = to[fa[x] ^ 1];
+        }
+    }
+    return flow;
+}
+int main()
+{
+    memset(head, -1, sizeof(head));
+    int n, m;
+    scanf("%d%d", &n, &m);
+    cnt = n + 2;
+    for (int i = 1, x; i <= n; i++)
+    {
+        scanf("%d", &x);
+        if (x) addEdge(0, i, 1);
+        else addEdge(i, n + 1, 1);
+    }
+    for (int i = 1, x, y; i <= m; i++)
+    {
+        scanf("%d%d", &x, &y);
+        addEdge_impl_(x, y, 1);
+        addEdge_impl_(y, x, 1);
+    }
+    printf("%d", ISAP(0, n + 1));
+    return 0;
+}
\ No newline at end of file