機房測試10.7
阿新 • • 發佈：2018-10-07
amp 技術分享 ges string edge 名單 clas inf stdin
題解之前
今天是三體的題目背景，比什麽美好的每一天好理解多了。
水滴
難得的NOIP模擬題，滑窗解決。
也可以二分區間長度，再進行統計。
我的\(nlogn\)算法
#include<cstdio> #include<cstring> #include<algorithm> #include<iostream> #include<ctime> #define FN "drop" const int maxn=2e5+5; int dan[maxn]; int cnt[maxn]; int need[maxn]; int n,k,R; bool check(int len) { memset(cnt,0,sizeof cnt); int res=R; for(int i=1;i<=len;i++) { cnt[dan[i]]++; if(cnt[dan[i]]==need[dan[i]]) --res; if(!res) return true; } for(int l=2,r=len+1;r<=n;l++,r++) { --cnt[dan[l-1]]; if(cnt[dan[l-1]]==need[dan[l-1]]-1) ++res; ++cnt[dan[r]]; if(cnt[dan[r]]==need[dan[r]]) --res; if(!res) return true; } return false; } int main() { freopen(FN".in","r",stdin); freopen(FN".out","w",stdout); int T;scanf("%d",&T); while(T--) { memset(need,0,sizeof need); memset(dan,0,sizeof dan); scanf("%d%d%d",&n,&k,&R); for(int i=1;i<=n;i++) scanf("%d",dan+i); for(int i=1;i<=R;i++) { int c,num;scanf("%d%d",&c,&num); need[c]=num; } int l=0,r=n+1,ans=-1; while(l<r) { int mid=l+r>>1; if(check(mid)) { ans=mid; r=mid; } else l=mid+1; } if(!~ans) printf("DESTROY ALL\n"); else printf("%d\n",ans); } return 0; }
std的O(n)算法
#include<cstdio> #include<algorithm> using namespace std; const int MAXN = 200000; int D[MAXN + 5], ned[MAXN + 5]; int tot[MAXN + 5], nw[MAXN + 5]; void solve() { int N, K, R; scanf("%d%d%d", &N, &K, &R); for(int i=0;i<K;i++) ned[i] = tot[i] = 0; for(int i=1;i<=N;i++) { scanf("%d", &D[i]); tot[D[i]]++; } for(int i=1;i<=R;i++) { int B, Q; scanf("%d%d", &B, &Q); ned[B] = Q; } for(int i=0;i<K;i++) if( tot[i] < ned[i] ) { puts("DESTROY ALL"); return ; } int ans = N, re = R, le = 1, ri = 0; while( le <= N ) { while( ri + 1 <= N && re ) { nw[D[++ri]]++; if( nw[D[ri]] == ned[D[ri]] ) re--; } if( !re ) ans = min(ans, ri-le+1); if( nw[D[le]] == ned[D[le]] ) re++; nw[D[le++]]--; } printf("%d\n", ans); } int main() { freopen("drop.in", "r", stdin); freopen("drop.out", "w", stdout); int T; scanf("%d", &T); for(int i=1;i<=T;i++) solve(); }
“神“
2-SAT裸題？
一眼看出來2-SAT，邊都連好了，寫不來算法。
太菜了。
#include<cstdio> #include<algorithm> using namespace std; const int MAXN = 5000; struct edge{ int to; edge *nxt; }edges[2*MAXN + 5], *adj[MAXN + 5], *ecnt=&edges[0]; void addedge(int u, int v) { edge *p = (++ecnt); p->to = v, p->nxt = adj[u], adj[u] = p; } void init() { ecnt = &edges[0]; for(int i=0;i<=MAXN;i++) adj[i] = NULL; } bool vis[MAXN + 5]; void dfs(int x) { vis[x] = true; for(edge *p=adj[x];p!=NULL;p=p->nxt) if( !vis[p->to] ) dfs(p->to); } void solve() { init(); int N, M; scanf("%d%d", &N, &M); for(int i=1;i<=M;i++) { int u, v; scanf("%d%d", &u, &v); if( u < 0 ) u = (-u-1)<<1|1; else u = (u-1)<<1; if( v < 0 ) v = (-v-1)<<1|1; else v = (v-1)<<1; addedge(u, v^1); addedge(v, u^1); } int ans = 3; for(int i=0;i<N;i++) { bool f1 = false, f2 = false, f3 = false; for(int j=0;j<(N<<1);j++) vis[j] = false; dfs(i<<1); f1 = vis[i<<1|1]; for(int j=0;j<(N<<1);j++) vis[j] = false; dfs(i<<1|1); f2 = vis[i<<1]; for(int j=0;j<N;j++) f3 = f3 || vis[j<<1]; if( f1 && f2 ) ans = min(ans, 0); else if( f2 ) ans = min(ans, 1); else if( f3 ) { if( f1 ) ans = min(ans, 1); else ans = min(ans, 2); } } if( ans == 3 ) puts("No Way"); else printf("%d\n", ans); } int main() { freopen("god.in", "r", stdin); freopen("god.out", "w", stdout); int T; scanf("%d", &T); for(int i=1;i<=T;i++) solve(); }
執劍人
貪心+數據結構。
只會貪心，於是只有60分。
用後綴和來選出槍斃名單。
用棧存從一邊開始的槍斃名單，線段樹從另外一邊開始操作。
#include<cstdio>
#include<vector>
#include<algorithm>
using namespace std;
const int INF = (1<<30);
const int MAXN = 500000;
struct query{
int ri, ind;
query(int _r, int _i):ri(_r), ind(_i){}
};
vector<query>qry[MAXN + 5];
char str[MAXN + 5];
int stk[MAXN + 5], ans[MAXN + 5], top;
struct node{
int mss, sum;
int le, ri;
}tree[4*MAXN + 5];
void PushUp(int x) {
tree[x].mss = min(tree[x<<1|1].mss, tree[x<<1].mss + tree[x<<1|1].sum);
tree[x].sum = tree[x<<1].sum + tree[x<<1|1].sum;
}
void Build(int x, int l, int r) {
tree[x].le = l, tree[x].ri = r;
if( l == r ) {
tree[x].mss = tree[x].sum = 0;
return ;
}
int mid = (l + r) >> 1;
Build(x<<1, l, mid);
Build(x<<1|1, mid+1, r);
PushUp(x);
}
void Modify(int x, int pos, int key) {
if( pos > tree[x].ri || pos < tree[x].le )
return ;
if( tree[x].le == tree[x].ri ) {
tree[x].sum = tree[x].mss = key;
return ;
}
Modify(x<<1, pos, key);
Modify(x<<1|1, pos, key);
PushUp(x);
}
node Query(int x, int pos) {
if( tree[x].ri <= pos )
return tree[x];
int mid = (tree[x].le + tree[x].ri) >> 1;
if( pos <= mid )
return Query(x<<1, pos);
else {
node ret = Query(x<<1|1, pos);
ret.mss = min(ret.mss, ret.sum + tree[x<<1].mss);
ret.sum = ret.sum + tree[x<<1].sum;
return ret;
}
}
inline int Read() {
char ch = getchar(); int x = 0, f = 1;
while( (ch > ‘9‘ || ch < ‘0‘) && ch != ‘-‘ ) ch = getchar();
if( ch == ‘-‘ ) f = -1, ch = getchar();
while( ‘0‘ <= ch && ch <= ‘9‘ )
x = 10*x + ch-‘0‘, ch = getchar();
return x * f;
}
int main() {
freopen("sworder.in", "r", stdin);
freopen("sworder.out", "w", stdout);
int N, Q;
scanf("%d%s%d", &N, str+1, &Q);
for(int i=1;i<=Q;i++) {
int l, r;
l = Read(), r = Read();
qry[l].push_back(query(r, i));
}
Build(1, 1, N); top = N+1;
for(int i=N;i>=1;i--) {
if( str[i] == ‘C‘ )
stk[--top] = i;
else {
if( top != N+1 ) {
Modify(1, stk[top], -1);
stk[top++] = 0;
}
Modify(1, i, 1);
}
for(int j=0;j<qry[i].size();j++) {
int p = upper_bound(stk+top, stk+N+1, qry[i][j].ri) - stk;
ans[qry[i][j].ind] = (p-top) - min(0, Query(1, qry[i][j].ri).mss);
}
}
for(int i=1;i<=Q;i++)
printf("%d\n", ans[i]);
}
於是今天愉快地拿到了大眾分數。
機房測試10.7