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lecture_notes:04-22-2011 [2011/06/08 17:14] eyliaw [Suffix array] |
lecture_notes:04-22-2011 [2011/06/08 17:29] eyliaw [Suffix array] |
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GOOGOL | GOOGOL | ||
Append end character: | Append end character: | ||
- | GOOGOL$ | + | X = GOOGOL$ |
Cyclic transformation: | Cyclic transformation: | ||
0 GOOGOL$ | 0 GOOGOL$ | ||
Line 32: | Line 32: | ||
The Burrows Wheeler transform takes the last character of the sorted cyclic strings: | The Burrows Wheeler transform takes the last character of the sorted cyclic strings: | ||
B(i) = LO$OOGG | B(i) = LO$OOGG | ||
+ | ===== Searching ===== | ||
+ | We can use the FM-index to find the upper and lower bounds of a substring. | ||
+ | C_X(a) is the number of characters lexicographically before a in X. | ||
+ | $ 0 | ||
+ | G 1 | ||
+ | L 3 | ||
+ | O 4 | ||
+ | O_X(a,i) is the number of occurrences of a in B_X[0,i]. |