#include <cstdio> #include <vector> struct Tree { int *mins; int *sums; int s; Tree(int size) { s=1; while (s<size) s<<=1; mins = new int[2*s]; sums = new int[2*s]; for (int i=0;i<2*s;++i) mins[i] = sums[i] = 0; } ~Tree() { delete []mins; delete []sums; } void set(int p, int v) { sums[p+s] = v; mins[p+s] = v; for (p=(p+s)>>1; p; p>>=1) { sums[p] = sums[2*p]+sums[2*p+1]; mins[p] = std::min(mins[2*p], sums[2*p]+mins[2*p+1]); } } //minimalna suma od elementow [p,x] x<=k int getmin(int p, int k) { std::vector<int> pos1; std::vector<int> pos2; p += s; k += s; while (p < k) { if (p&1) pos1.push_back(p++); if (!(k&1)) pos2.push_back(k--); p>>=1; k>>=1; } if (p==k) pos1.push_back(p); pos1.insert(pos1.end(),pos2.rbegin(),pos2.rend()); int cm = mins[pos1[0]]; int cs = sums[pos1[0]]; for (int i=1; i<pos1.size(); ++i) { cm = std::min(cm, cs+mins[pos1[i]]); cs = cs+sums[pos1[i]]; } return cm; } //we know that such element exists int findnear(int p,int val) { static int ssum[30]; static int smin[30]; static int slast[30]; int pos = 0; p+=s; ssum[0]=sums[p]; smin[0]=mins[p]; slast[0]= (p&1)?0:-1; pos = 1; while (smin[pos-1]>val && p>1) { int parent = slast[pos-1]; p = (p+1)>>1; if (parent==-1) { ssum[pos]=sums[p]; smin[pos]=mins[p]; } else { smin[pos]=std::min(smin[parent], ssum[parent]+mins[p]); ssum[pos]=ssum[parent]+sums[p]; } if (p&1) slast[pos]=pos; else slast[pos]=parent; pos++; } int cs = (slast[pos-2]>=0)?ssum[slast[pos-2]]:0; int cm = (slast[pos-2]>=0)?smin[slast[pos-2]]:1000000000; while (p<s) { if (val >= std::min(cm, cs+mins[2*p])) { p = 2*p; } else { cm = std::min(cm, cs+mins[2*p]); cs = cs+sums[2*p]; p = 2*p+1; } } return p-s; } }; int N,M; int start[1000100]; int cycle[1000100]; int position[1000100]; int chain[1000100]; std::vector<int> chain_sums[1000100]; std::vector<Tree*> trees; int next(int x) { return (x+N)%M; } int getsum(int nr, int l, int r) { if (l==0) return chain_sums[nr][r]; if (l<=r) return chain_sums[nr][r] - chain_sums[nr][l-1]; return getsum(nr,l,chain_sums[nr].size()-1) + getsum(nr,0,r); } //minimalna wartosc sumy int getmin(int nr,int l, int r) { if (l<=r) return trees[nr]->getmin(l,r); else return std::min(trees[nr]->getmin(l,chain_sums[nr].size()-1), getsum(nr,l,chain_sums[nr].size()-1) + trees[nr]->getmin(0,r) ); } //najblizszy taki, ze suma to val int findnear(int nr,int l,int val) { int size = chain_sums[nr].size(); if (val >= trees[nr]->getmin(l,size-1)) { return trees[nr]->findnear(l,val); } else { return trees[nr]->findnear(0,val-getsum(nr,l,size-1)); } } int main() { scanf("%d",&N); for (int i=0;i<N;++i) { scanf("%d",&start[i]); } scanf("%d\n",&M); for (int i=0;i<M;++i) { char c; scanf("%c",&c); cycle[i] = (c=='W')?1:-1; position[i] = -1; chain[i] = -1; } //budowa cykli int nr = 0; for (int i=0; i<M; ++i) { if (chain[i] == -1) { int x = i; int pos = 0; int lsum = 0; int len = 1; int xx = next(x); while (xx != x) { ++len; xx = next(xx); } trees.push_back(new Tree(len)); while (chain[x] == -1) { chain[x] = nr; position[x] = pos; chain_sums[nr].push_back(lsum + cycle[x]); trees.back()->set(pos,cycle[x]); x = next(x); lsum = chain_sums[nr].back(); pos++; } nr++; } } //szukanie odpowiedzi long long int result = -1; for (int i=0; i<N; ++i) { int first = i % M; int chain_nr = chain[first]; int chain_pos = position[first]; int chain_length = chain_sums[chain_nr].size(); int chain_sum = chain_sums[chain_nr].back(); if (chain_sum>=0) { int min = getmin(chain_nr,chain_pos,(chain_pos+chain_length-1)%chain_length); if (start[i] + min <= 0) { int near = findnear(chain_nr,chain_pos,-start[i]); long long int turns = (chain_length+near-chain_pos)%chain_length; long long int end = turns * ((long long int) N) + i + 1; if (result == -1 || end < result) result = end; } } else { int min = getmin(chain_nr,chain_pos,(chain_pos+chain_length-1)%chain_length); long long int end = 0; if (start[i] + std::min(chain_sum,min) > 0) { long long int turns = (start[i] + std::min(chain_sum,min))/(-chain_sum); end = turns*chain_length*N; start[i] += chain_sum*turns; while (start[i]+std::min(chain_sum,min) > 0) { end += (long long int)chain_length*N; start[i] += chain_sum; } } if (start[i] == -chain_sum && -min < -chain_sum) { end += (long long int)chain_length*N + i + 1; } else { int near = findnear(chain_nr,chain_pos,-start[i]); long long int t = (chain_length+near-chain_pos)%chain_length; end += t * ((long long int) N) + i + 1; } if (result == -1 || end < result) result = end; } } printf("%lld\n",result); return 0; }
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 | #include <cstdio> #include <vector> struct Tree { int *mins; int *sums; int s; Tree(int size) { s=1; while (s<size) s<<=1; mins = new int[2*s]; sums = new int[2*s]; for (int i=0;i<2*s;++i) mins[i] = sums[i] = 0; } ~Tree() { delete []mins; delete []sums; } void set(int p, int v) { sums[p+s] = v; mins[p+s] = v; for (p=(p+s)>>1; p; p>>=1) { sums[p] = sums[2*p]+sums[2*p+1]; mins[p] = std::min(mins[2*p], sums[2*p]+mins[2*p+1]); } } //minimalna suma od elementow [p,x] x<=k int getmin(int p, int k) { std::vector<int> pos1; std::vector<int> pos2; p += s; k += s; while (p < k) { if (p&1) pos1.push_back(p++); if (!(k&1)) pos2.push_back(k--); p>>=1; k>>=1; } if (p==k) pos1.push_back(p); pos1.insert(pos1.end(),pos2.rbegin(),pos2.rend()); int cm = mins[pos1[0]]; int cs = sums[pos1[0]]; for (int i=1; i<pos1.size(); ++i) { cm = std::min(cm, cs+mins[pos1[i]]); cs = cs+sums[pos1[i]]; } return cm; } //we know that such element exists int findnear(int p,int val) { static int ssum[30]; static int smin[30]; static int slast[30]; int pos = 0; p+=s; ssum[0]=sums[p]; smin[0]=mins[p]; slast[0]= (p&1)?0:-1; pos = 1; while (smin[pos-1]>val && p>1) { int parent = slast[pos-1]; p = (p+1)>>1; if (parent==-1) { ssum[pos]=sums[p]; smin[pos]=mins[p]; } else { smin[pos]=std::min(smin[parent], ssum[parent]+mins[p]); ssum[pos]=ssum[parent]+sums[p]; } if (p&1) slast[pos]=pos; else slast[pos]=parent; pos++; } int cs = (slast[pos-2]>=0)?ssum[slast[pos-2]]:0; int cm = (slast[pos-2]>=0)?smin[slast[pos-2]]:1000000000; while (p<s) { if (val >= std::min(cm, cs+mins[2*p])) { p = 2*p; } else { cm = std::min(cm, cs+mins[2*p]); cs = cs+sums[2*p]; p = 2*p+1; } } return p-s; } }; int N,M; int start[1000100]; int cycle[1000100]; int position[1000100]; int chain[1000100]; std::vector<int> chain_sums[1000100]; std::vector<Tree*> trees; int next(int x) { return (x+N)%M; } int getsum(int nr, int l, int r) { if (l==0) return chain_sums[nr][r]; if (l<=r) return chain_sums[nr][r] - chain_sums[nr][l-1]; return getsum(nr,l,chain_sums[nr].size()-1) + getsum(nr,0,r); } //minimalna wartosc sumy int getmin(int nr,int l, int r) { if (l<=r) return trees[nr]->getmin(l,r); else return std::min(trees[nr]->getmin(l,chain_sums[nr].size()-1), getsum(nr,l,chain_sums[nr].size()-1) + trees[nr]->getmin(0,r) ); } //najblizszy taki, ze suma to val int findnear(int nr,int l,int val) { int size = chain_sums[nr].size(); if (val >= trees[nr]->getmin(l,size-1)) { return trees[nr]->findnear(l,val); } else { return trees[nr]->findnear(0,val-getsum(nr,l,size-1)); } } int main() { scanf("%d",&N); for (int i=0;i<N;++i) { scanf("%d",&start[i]); } scanf("%d\n",&M); for (int i=0;i<M;++i) { char c; scanf("%c",&c); cycle[i] = (c=='W')?1:-1; position[i] = -1; chain[i] = -1; } //budowa cykli int nr = 0; for (int i=0; i<M; ++i) { if (chain[i] == -1) { int x = i; int pos = 0; int lsum = 0; int len = 1; int xx = next(x); while (xx != x) { ++len; xx = next(xx); } trees.push_back(new Tree(len)); while (chain[x] == -1) { chain[x] = nr; position[x] = pos; chain_sums[nr].push_back(lsum + cycle[x]); trees.back()->set(pos,cycle[x]); x = next(x); lsum = chain_sums[nr].back(); pos++; } nr++; } } //szukanie odpowiedzi long long int result = -1; for (int i=0; i<N; ++i) { int first = i % M; int chain_nr = chain[first]; int chain_pos = position[first]; int chain_length = chain_sums[chain_nr].size(); int chain_sum = chain_sums[chain_nr].back(); if (chain_sum>=0) { int min = getmin(chain_nr,chain_pos,(chain_pos+chain_length-1)%chain_length); if (start[i] + min <= 0) { int near = findnear(chain_nr,chain_pos,-start[i]); long long int turns = (chain_length+near-chain_pos)%chain_length; long long int end = turns * ((long long int) N) + i + 1; if (result == -1 || end < result) result = end; } } else { int min = getmin(chain_nr,chain_pos,(chain_pos+chain_length-1)%chain_length); long long int end = 0; if (start[i] + std::min(chain_sum,min) > 0) { long long int turns = (start[i] + std::min(chain_sum,min))/(-chain_sum); end = turns*chain_length*N; start[i] += chain_sum*turns; while (start[i]+std::min(chain_sum,min) > 0) { end += (long long int)chain_length*N; start[i] += chain_sum; } } if (start[i] == -chain_sum && -min < -chain_sum) { end += (long long int)chain_length*N + i + 1; } else { int near = findnear(chain_nr,chain_pos,-start[i]); long long int t = (chain_length+near-chain_pos)%chain_length; end += t * ((long long int) N) + i + 1; } if (result == -1 || end < result) result = end; } } printf("%lld\n",result); return 0; } |