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56 lines
1.3 KiB
C++
56 lines
1.3 KiB
C++
#include <cctype>
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#include <cstdio>
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inline int min(int a, int b) { return a < b ? a : b; }
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const int maxn = 1001;
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inline void getInt(int &x)
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{
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x = 0;
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int ch;
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while (!isdigit(ch = getchar()))
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;
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while (isdigit(ch))
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x = x * 10 + ch - '0', ch = getchar();
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}
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typedef struct Edge
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{
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int to;
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Edge *next;
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Edge(int t, Edge *n) : to(t), next(n) {}
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} * lpEdge;
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lpEdge G[maxn];
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int Low[maxn], DFN[maxn], st[maxn], s_top, DFNcnt, SCC[maxn], SCCcnt;
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bool instack[maxn];
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#define addEdge(x, y) G[x] = new Edge(y, G[x])
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void tarjan(int id)
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{
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instack[id] = true;
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DFN[id] = Low[id] = ++DFNcnt;
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st[s_top++] = id;
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for (lpEdge cur = G[id]; cur; cur = cur->next)
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{
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if (!DFN[cur->to])
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tarjan(cur->to), Low[id] = min(Low[id], Low[cur->to]);
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else if (instack[cur->to])
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Low[id] = min(Low[id], DFN[cur->to]);
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}
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if (DFN[id] == Low[id])
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{
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SCCcnt++;
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do
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s_top--,
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SCC[st[s_top]] = SCCcnt,
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instack[st[s_top]] = false;
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while (st[s_top] != id);
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}
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}
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int main()
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{
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int n;
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getInt(n);
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for (int i = 0, x, y; i < n; i++)
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getInt(x), getInt(y), addEdge(x, y);
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tarjan(1);
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for (int i = 0; i < 10; i++)
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printf("%d : %d\n", i, SCC[i]);
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return 0;
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} |