6 #define W (8*sizeof(int))
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7 #define logW 5 // code checks = lg(W)-1
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8 #define divW(p) ((p)>>logW)
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9 #define modW(p) ((p)&(W-1))
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11 #define setBit(arr,pos) ((arr)[divW(pos)] |= 1<<modW(pos))
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12 #define clearBit(arr,pos) ((arr)[divW(pos)] &= ~(1<<modW(pos)))
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13 #define getBit(arr,pos) ((arr)[divW(pos)] & (1<<modW(pos))) // 0 or !=0
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15 static int lg (int n)
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18 while (n) { n>>=1; answ++; }
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22 results createResults (int n)
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25 if (logW != lg(W)-1)
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26 { fprintf(stderr,"Error, redefine logW as %i and recompile\n",lg(W)-1);
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31 R.tree = (int*) malloc (((R.n+W-1)/W)*sizeof(int));
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32 clearBit(R.tree,0); // clear all
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36 void freeResults (results R)
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41 // to map 1..n to the bottom of the tree when n is not a power of 2
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42 static int conv (int p, int n, int lgn)
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44 { int t = n+1-(1<<lgn);
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45 if (p < t) return p;
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49 static int unconv (int p, int n, int lgn)
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51 { int t = n+1-(1<<lgn);
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52 if (p < t) return p;
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56 int readResult (results R, int p) // returns 0 or 1
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62 do { if (!getBit(R.tree,pos)) return 0;
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64 pos = (pos<<1)+1+(p>>pot);
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71 void setResult (results R, int p)
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78 do { npos = (pos<<1)+1;
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79 if (!getBit(R.tree,pos))
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80 { setBit(R.tree,pos);
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82 { clearBit(R.tree,npos);
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83 clearBit(R.tree,npos+1);
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87 pos = npos+(p>>pot);
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93 // returns final value of bit at pos
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95 static int clearRangeLeft (int *tree, int p1, int n, int pos, int pot)
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99 if (!getBit(tree,pos)) return 0; // range already zeroed
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101 if (p1 == 0) // full range to clear
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102 { clearBit(tree,pos); return 0; }
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103 // p1 != 0, there must be children
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106 if ((p1>>pot) == 0) // go left, clear right
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107 { clearBit(tree,npos+1);
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108 bit = clearRangeLeft(tree,p1,n,npos,pot);
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111 { bit = clearRangeLeft(tree,p1,n,npos+1,pot);
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112 if (!bit) bit = getBit(tree,npos);
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114 if (!bit) clearBit(tree,pos);
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118 static int clearRangeRight (int *tree, int p2, int n, int pos, int pot)
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122 if (!getBit(tree,pos)) return 0; // range already zeroed
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124 if (p2 == 0) return 1; // empty range to clear, and bit is 1 for sure
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125 // p2 != 0, there must be children
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128 if ((p2>>pot) == 1) // go right, clear left
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129 { clearBit(tree,npos);
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130 bit = clearRangeRight(tree,p2,n,npos+1,pot);
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133 { bit = clearRangeRight(tree,p2,n,npos,pot);
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134 if (!bit) bit = getBit(tree,npos+1);
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136 if (!bit) clearBit(tree,pos);
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140 static int clearBoth (int *tree, int n, int p1, int p2, int pos, int pot)
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142 { int npos,npos1,npos2;
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144 if (!getBit(tree,pos)) return 0; // range is already zeroed
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146 // children must exist while the path is unique, as p1<p2
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148 npos1 = npos+(p1>>pot);
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149 npos2 = npos+(p2>>pot);
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150 if (npos1 == npos2) // we're inside npos1=npos2
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151 { bit = clearBoth (tree,n,p1&~(1<<pot),p2&~(1<<pot),npos1,pot);
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152 bit |= getBit(tree,npos+1-(p1>>pot)); // the other
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154 else // p1 and p2 take different paths here
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155 { bit = clearRangeLeft(tree,p1,n,npos1,pot);
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156 bit |= clearRangeRight(tree,p2,n,npos2,pot);
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158 if (!bit) clearBit(tree,pos);
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162 void clearRange (results R, int p1, int p2)
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164 { if ((p2+1)<<1 > R.n)
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165 clearRangeLeft(R.tree,conv(p1,R.n,R.lgn),R.n,0,R.lgn);
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166 else clearBoth(R.tree,R.n,conv(p1,R.n,R.lgn),conv(p2+1,R.n,R.lgn),0,R.lgn);
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169 static int nextSmallest (int *tree, int n, int pos, int pot)
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175 if (pos >= n) return p;
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176 if (!getBit(tree,pos)) { pos++; p |= (1<<pot); }
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180 static int nextLarger (int *tree, int n, int p, int pos, int pot)
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183 if (!getBit(tree,pos)) return -1; // no answer
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186 if (pos >= n) return 0; // when n is not a power of 2, missing leaves
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187 if ((p>>pot) == 0) // p goes left
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188 { answ = nextLarger(tree,n,p&~(1<<pot),pos,pot);
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189 if (answ != -1) return answ;
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190 if (!getBit(tree,pos+1)) return -1; // no answer
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191 return (1<<pot) | nextSmallest(tree,n,pos+1,pot);
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194 { answ = nextLarger(tree,n,p&~(1<<pot),pos+1,pot);
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195 if (answ != -1) return (1<<pot) | answ;
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200 int nextResult (results R, int p) // returns pos of next(p) or -1 if none
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203 if (((p+1)<<1) > R.n) return -1; // next(last), p+1 out of bounds
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204 answ = nextLarger(R.tree,R.n,conv(p+1,R.n,R.lgn),0,R.lgn);
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205 if (answ == -1) return -1;
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206 return unconv(answ,R.n,R.lgn);
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209 static void prnspace (int k)
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211 { while (k--) putchar(' ');
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214 void printTree (results R)
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222 prnspace((1<<(pot-1))-1);
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223 while (lnum-- && n--)
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224 { putchar (getBit(R.tree,pos) ? '1' : '0');
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226 prnspace((1<<pot)-1);
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